The Origins of the King’s German Legion 1803-04 and the Expedition to Hanover, 1805.
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The Origins of the King’s German Legion 1803-04
and the Expedition to Hanover, 1805.
The King’s German Legion is one of the best-known and highly-regarded fighting forces which served under British command during the Napoleonic Wars. They were the only German forces to remain continually in action against the French between 1803-1815. Originally raised from elements of the disbanded Hanoverian Army, along with citizens as volunteers and, to a lesser extent, other foreign nationals (like ex-French prisoners of war from their German regiments), it eventually raised over 28,000 men to serve under arms in the British cause. This is a huge number of men to remove from one small-ish area and one wonders what the impact must have been on families, relationships, businesses and agriculture with the loss of so many working men, most of them absent for up to 10 years.

An early view of the city of Hanover
The German principality of Hanover (or Hannover in German usage) was at that time a possession of the British crown – kings of England from George I to William IV (the ‘Hannoverian Dynasty’, 1714-1837) were rulers of the German state and also ‘Electors’ within the Holy Roman Empire and its fall to French forces in 1803 was, amongst other things, a significant propaganda victory for the French over their British antagonists.

Britain and Hanover
When the French took control of Hanover, its army, which had not opposed the French occupation, was simply disbanded and dispersed. But many of its officers and men were determined to continue the fight and to take up arms against the invader and occupier of their homeland. There are strong echoes of what happened next during the Second World War when large numbers of men from the occupied continent made their way to Britain to continue the fight, joining “free” forces from Poland, Czechoslovakia, France etc.
The simple hope in 1803 that most of the standing Hanoverian army could be transferred to Britain by the Royal Navy was soon dispelled; the French were certainly not going to allow the easy movement of potential enemies and quickly laid down severe penalties for any ex-soldier (and later indeed, anyone else) who sought to leave Hanover to travel to Britain to join the army. As early as the Winter of 1803, the French announced the confiscation of officers’ property and it later became a death-penalty offence to make the attempt.
At this time – July 1803 – Lt. Col. Frederick von der Decken, Master General of the Hanoverian Ordnance and Staff Officer to the Duke of Cambridge, was in England along with other German officers discussing possible options. He was given authority to open an office in London to try to recruit a “foreign corps” of up to 4,000 men drawn from Hanover. Colonel Colin Hackett was also ordered to raise an artillery arm to the force. Information was disseminated by leaflet and poster in Hanover and all former officers and men of the Hanoverian army were urged to make their way to Britain if they wished to continue their fight against the French. At the same time, a Royal Edict was issued absolving King George’s Hanoverian subjects from any adhesion to French laws or proclamations; Royal Navy warships and merchant vessels cruising off Denmark and northern Germany were officially ordered to pick up and give free passage to any Hanoverian officer, soldier or citizen who wished to make the voyage. In December 1804, a treaty with Sweden even allowed the setting up of recruitment offices in the Hanseatic port of Stralsund in Pomerania and on the island of Rugen itself, both then under Swedish rule.
One cannot over-emphasise the difficulty which was faced by most of the ex-soldiers and later volunteers who tried to make the journey from Hanover to England – despite the fact that so many thousands eventually did. Most of the initial recruits were ex-officers – men with enough money and resources (horses and carriages!) to get themselves out of Germany and en route to Britain (e.g. the surgeon J. F. Hering who travelled by carriage and boat). For the ex-soldiers and volunteers, it was a journey fraught with difficulties and real danger. Most of the “ordinary” soldiers and working men would simply have to walk from their homes, farms or villages to the north coast of Germany or to the Danish frontier in Holstein (where the Danish king kindly gave permission to cross) or to Heligoland and then rendezvous with British ships to take them to England.
In due course – and again reminiscent of occupied Europe in the Second World War – a complex network of German/ Hanoverian recruiters and agents was established in towns and villages in Hanover, with “safe houses”, covert routes and reliable guides, recruiting men and helping volunteers to make their way out of the country. The British eventually set up a base on Heligoland off the mouth of the Elbe (taken from Denmark in 1807) as an advanced organisational base and from here recruiting agents dispersed through Hanover to attract new recruits and arrange their journey. This was very dangerous work – but well-paid!

Lt. Genl. Conrad Poten – a teenage recruit into the KGL cavalry.
It is unfortunate that so few accounts of these journeys have survived, but they must have been adventures in themselves, even before getting into action with the French! One of the volunteers, Conrad Poten, who became a distinguished KGL cavalry officer and later General in the Hanoverian Army, recalled that at not quite the age of 15 he was so obsessed with the idea of “joining up” that he tagged along with a troupe of performers and musicians who busked their way to the Weser, where he found a smuggler who conveyed him to Heligoland and then took ship to England. Some went by wagon or barge but the majority of working men and labourers simply had to walk to the northern coast and most were men who had never seen the sea, before facing a difficult and dangerous voyage to England! Others recalled the terrible overcrowding and poor conditions on some of the ships and days of seasickness! And there was always the chance of being attacked by cruising French warships.
In July 1803, as preliminary moves were being made to form a “foreign legion”, it was decreed that if 400 men were not raised within three months, the plan was to be abandoned and initially, the response was worryingly weak – the first recruits were mainly former Hanoverian officers who had the means to get out of Hanover, so that there were at first far more officers than men and it looked as if the aim to raise 400 men, let alone a corps of 4,000 men, would not be achieved.

Hanoverian medal to the Volunteers of the King’s German Legion. Awarded in 1841 – those who received the MGS in 1848 might also wear this.
Recruits who made their way to England would be directed to a new depot, first set up at Lymington in Hampshire, and German officers were based in port destinations like London, Plymouth and Harwich to direct recruits to Lymington. Only as 1803 progressed did the system kick into action in Hanover and more and more men got the message and took the risk – in the face of increased French reprisals. By November, the number of recruits had reached many hundreds and a new training centre and depot had to be opened at Parkhurst on the Isle of Wight to deal with what was initially (August 1803) called The King’s German Regiment. A new Recruiting Patent of December 1803 ordered the raising of a German corps of 5,000 men “of all arms” and by the very end of December, a cavalry and horse-artillery depot had been set up at Radipole near Weymouth (and one later in Dorchester), with one for foot artillery at Hilsea, near Portsmouth; the south coast was chosen for these bases simply to add weight to Britain’s coastal defences in the face of possible French invasion.

Line infantry, Light Infantry and Hussar of the KGL
Thus, within six months of the dissolution of the Hanoverian army in its homeland, substantial numbers of its men had re-assembled in Britain and were re-named The King’s German Legion in December 1803. Most of the artillery and mounted volunteers were ex- soldiers of those branches in the former Hanoverian army and the cavalry were initially organised into four troops of heavy cavalry and four of light. Infantry recruits were formed into two Light Battalions (riflemen) and one Line Battalion. In April – May 1804, a Second and Third Line regiment were raised, followed by a Fourth a few months later; the Light Infantry battalions were formed into a LI Brigade under Colonel Charles von Alten and the others into a Line Brigade under Colonel von Langwerth.
From September 1804, the infantry (initially two Light and three Line battns.) was moved to a new base at Bexhill on the Sussex coast, then a small village which became the main centre of the King’s German Legion for the next ten years. Its inhabitants found themselves suddenly overwhelmed by German-speaking soldiers who were accommodated in large tented and later hutted camps around the town, the senior officers billeted in more substantial houses. They seem to have had good relations with the locals – they certainly brought a huge increase in trade to shops, inns and professions and there are many records of marriages! Interestingly, much remains to speak of the KGL presence there – the old KGL parade gound is still largely open land (some under allotments), the KGL cemetery is clearly marked and some of the local houses, buildings and the church in the “Old Town” would have been known to the some of the officers at least. Bexhill became a major garrison area and many other (British) regiments were stationed along with the KGL around the town as time went by.

Part of the “Old Town” at Bexhill – an area familiar to the KGL
The artillery was expanded to a second and third foot battery and a second horse battery in the Summer of 1804.
Uniforms in all branches of the King’s German Legion were essentially the same as those of the corresponding British services.
By the beginning of 1805, the KGL comprised the following corps, manned by Hanoverian officers and men who had made their way to England to the various KGL depots:
Cavalry
[Most of the cavalry volunteers were ex-cavalrymen of the old Hanoverian Army]
1st Dragoons [heavy cavalry] – Col. von Bock – Cavalry brigade under Major General von Linsingen
1st Hussars [light cavalry] – Col. Victor von Alten – Cavalry brigade under Maj. Gen. von Linsingen
Infantry
1st Light Battn. – Col. Chas. von Alten (Brigade commander) – LI Brigade
2nd Light Battn. – Lt. Col. Halkett – LI Brigade
1st Line Battn. – Col. von Ompteda – 1st Line Brigade
2nd Line Battn. – Col. von Barsse (Brigade commander) – 1st Line Brigade
3rd Line Battn. – Col. von Hinuber – 2nd Line Brigade.
4th Line Battn. – Col. von Langwerth (Brigade commander) – 2nd Line Brigade.
Artillery – under Col. von der Decken (Commandant) and Major Frederick von Linsingen
[Most of the artillery volunteers were trained ex-artillerymen of the old Hanoverian Army]
1st Horse Battery – Capt. G. J. Hartmann
2nd Horse Battery – Capt. Röttiger
1st Foot Battery – Capt. Brückmann
2nd Foot Battery – Capt. Kühlmann
3rd Foot Battery – Capt. Heise
Engineers – four officers.
Uniform types – Foot Arty., 1st Hussars, Light Battn., 1st Dragoons
.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.
The Campaign in Hanover, 1805
Many of the campaigns, expeditions and battles fought against the French after 1805 have justly been remembered, written about, commemorated and celebrated – like the great victories of the Peninsular War in Portugal, Spain (and southern France) between 1808-1814 or in the Caribbean, North America or the Far East and elsewhere.
Many more have not been given anything like the same attention or coverage and have really “fallen through the cracks” of research and publication. One of these was the expedition to Hanover in 1805, the last campaign under William Pitt, undertaken after the crushing victory of Trafalgar and, more importantly, the apparent removal of the threat of a French invasion of Britain via Boulogne. With Napoleon’s apparent intention (if it ever existed) to invade England being abandoned and the removal of his army southwards towards the Danube, Britain had a very large force suddenly freed from the needs of defence and capable of taking action overseas. It could initially make available 2 Divisions of Heavy and Light cavalry (over 9,500 men), 4 battns. of Guards and 40 of Line infantry, a Light Brigade of 4 Battns. under Sir John Moore, 6 Brigades of Horse Artillery and 10 of Foot, along with the usual support services, like the Waggon Train and Engineers. These forces could be used to strike at Napoleon on the continent with the aid (as was usual) of Britian’s allies, since Britain did not have the land force to tackle the French alone. The campaign, a sort of “B.E.F. in 1805” is of particular interest here given the role of the newly-consolidated King’s German Legion which played a prominent part in the operations and which represented its first “active service”.
The reasons for attacking Hanover are pretty clear – not only would it be seen as the defence and recovery of a British territory but it would also link into the overall strategy of the new “Third Coalition”, made up of Great Britain, Austria, the Holy Roman Empire, the Russian Empire, Naples, Sicily and Sweden. Prussia initially remained undecided or neutral – and Napoleon continued to dangle the possibility of allowing a Prussian take-over of Hanover if she remained beyond the coalition. But it was hoped that British military intervention as a show of strength would press Prussia into the alliance – a major consideration in the diplomacy that ensued. In accordance with the aims of the alliance, Britain agreed to send an army to liberate Hanover and support the allied war in northern Europe, perhaps moving towards Holland or the Rhine in concert with Austrian and Russian operations. Ultimately, action to liberate Holland remained a major British strategic concern.
Of course, the army intended for Hanover would be a much smaller force than the total available – those initially chosen were the King’s German Legion (2 cavalry regiments and six infantry battalions), a Brigade of Guards and a Line Brigade, totalling some 15,000 men. As early as 17th September 1805, The Times reported :
“A number of regiments which are under orders for foreign service will embark at Portsmouth. The whole of the Hanoverian troops in this country will most probably be engaged in the expedition. The artillery, and six battalions of the German Legion, now encamped at Bexhill, have received orders to hold themselves in preparation to embark.”
Initial Expeditionary Force:
Kings German Legion infantry (approx. 6,000) – ordered to embark under General Don on 10th October.
KGL Cavalry (approx. 600) – ordered to embark on 10th October.
Guards Brigade (approx. 2,000)
4th Foot
14th Foot
23rd Fuslrs
95th Rifles x 4 cos. = approx. 400
2 Brigades of Artillery
The KGL element of the British force was initially placed under General Sir George Don, who was first sent to Berlin to negotiate with Prussia. Nearly six thousand men were derived from the King’s German Legion – just about their entire available force apart from two battalions based at Gibraltar and others still forming. Delayed by gales, but eventually leaving from Ramsgate for the mouth of the Elbe in November 1805, the expedition immediately came to grief amidst severe storms which scattered the transports – and did far more damage to the force than the French ever did. The KGL Hussars were driven onto the coast of Holland and the Heavy Dragoons forced to return to England (and never rejoined the force), while some of the 4th Line were driven ashore in northern Germany. Others of the KGL were assembled off Heligoland before proceeding to land. Despite these setbacks, on 18th and 19th November most of the British army was landed at Cuxhaven, receiving an ecstatic welcome by the local population who foresaw their liberation from French rule; it established magazines at Cuxhaven and Bremerlehe and then advanced via Dorum to Osterholz and thence into Bremen. Led by the 95th Rifles, it set up its head-quarters at Bremen and then marched to occupy the city of Hanover itself. A Prussian garrison there seemed at first unwilling to allow the British an entry but in the end did so and in fact the Prussians shortly afterwards withdrew from the state of Hanover.
Needless to say, it was a source of great pleasure and pride to the officers and men of the KGL to be involved in what appeared to be the liberation of their own country. One obvious danger, however, was that men who had been away from home and family would take the opportunity to desert. Unsurprisingly, there were plenty of cases of such desertions – but it is also recorded that many who left did return (after a spot of illegal “home leave”) and in fact the KGL eventually benefitted because so many young Hanoverian men were impressed with their look and bearing that they flocked to join and recruitment into the KGL went up sharply! Actual recruiting offices were set up in Stade and Hanover. It has been said that the greatest effect of the Hanover campaign was to increase the size of the KGL!

The Guelphic Medal for Gallantry. The first “named” gallantry award, given to both Hanoverian and KGL forces
To face the Austro-Russian coalition, Napoleon had withdrawn the vast majority of the French occupation army from Hanover, leaving only a strong garrison in the fortress-town of Hameln (Hamelin) and a force at Nienburg. The Russians initially led the investment of the fortress and were joined by the 1st KGL Line Brigade and 1st Foot Battery, with a KGL Engineer officer attached and two British infantry battalions. With a main base at Bremen, other British forces were stationed at Delmanhorst and Oldenburg, with others in towns along the river Weser, with their right wing at Blumenthal and their left at Verden; the KGL components were centred around Verden, ready for a planned advance on Nienberg, to deal with the small French presence.
With overall command of the British force placed in the hands of General Sir William Cathcart, (1755- 1843) in November 1805, reinforcements continued to arrive from England – a further 12,000 men, drawn from the 3rd, 5th, 9th, 26th, 36th and 89th Regiments landed in the Weser; many lost significant numbers in the gales and shipwrecks which beset them en route and some were seriously understrength. But in fact, the whole thing was already much too late and they arrived at exactly the time that Cathcart was proposing to withdraw the army altogether. The government’s hopes that, in face of a lack of allied action in the Hanoverian sphere, Cathcart could advance into Holland, were wildly optimistic given that he had severe transport and supply problems in what was a harsh winter and were soon abandoned. Nevertheless, eight more British battalions and reinforcements to the KGL cavalry were sent out in December.

Waterloo Medal of Gnr. C. Behrens, 1st Horse Batty, KGL Artillery. Given his date of enlistment – 9th Dec. 1805 – he may well have joined in Hanover.
The arrival in Hanover of the KGL was reported in The Times: “In the forenoon [Dec. 13th], the second battalion of the King’s German Legion entered this city, under Colonel Barsse. A vast crowd went out to meet their brave countrymen. Arrived upon the parade [sic] before the palace of the Duke of Cambridge, the Turkish music performed ‘God save the King,’ which was followed by loud acclamations. These troops, intended for the blockade of Hameln, will march to Pattensee in the course of the day.”
The Times reported on Dec. 19: “By accounts from our Army on the Continent, we are informed that Lieut. Gen. Don remained at Verden on the 8th inst. which place is the head-quarters of the British Army. The Guards are quartered in the environs of Bremen. The Russians have left Verden, in order to march to Hameln, which fortress is to be inmediately blockaded by them and the German Legion, under the command of Brigadier-General Decken.” The French are reported to have “thrown” a strong garrison into Hameln, ready to make some show of defence.
Later, it was reported from Hanover, that “on [Dec. 22nd], at two in the afternoon, between five and six hundred men of the garrison of Hameln, with some pieces of cannon, marched towards Springen. The English and Russians, on the first intelligence of this movement, marched to meet them, which gave occasion to a very obstinate action between Hochmuhlen and Alenhagen, which ended entirely in favour of the Russians and English. The French had a number of men killed and wounded, two hundred were made prisoners, and two pieces of cannon taken. They were obliged, towards evening, to retreat, to avoid being entirely cut off from Hameln. The two pieces of cannon, and the prisoners, were brought here to-day.” This was in fact the biggest action of the campaign but Hameln did not fall to the allies; the siege was later taken up by Prussian forces and the British contingent withdrew.
British forces, along with elements of the KGL, serving on the Weser by Jan. 1806:
Under Major General Sir Arthur Wellesley – 3rd Foot, 8th Foot, 36th Foot
Under Major General Fraser – 26th Foot, 28th Foot, 91st Foot
Under Major General Sherbrooke – 5th Foot, 27th Foot, 34th Foot
Other than these small actions, the military operations in “the Weser campaign” were not, in the end, very significant; Cathcart apparently “fought a small action at Munkaiser” but there seem to be no details on this in any major source. He was criticised for simply sitting and waiting for allied forces, especially those of Sweden and Russia, to move against Hanover and did nothing to take any firm action himself. But to be fair to him, he had also been ordered, apart from co-ordinating his actions with those of the Allies, not to engage in any campaigning which might “hazard” his army and not to engage in “unreasonable operations” in the depths of winter. He was at liberty to decline to act at all if he felt the circumstances were unfavourable. But in the end, it was not Cathcart’s inaction but Austro-Russian failure and the genius of Napoleon which doomed the exploit; “thwarting France by defending Hanover” was not enough by itself.
News travelled slowly. Even by the time that Cathcart’s army had left England, Napoleon had decisively turned the war against the allied coalition. As a result of the campaign of 16–19th October 1805 he had trapped an entire Austrian army under the command of General Mack von Leiberich with minimal losses and forced its surrender near Ulm in Bavaria. Only a month later, Napoleon entered Vienna, the Austrian capital. On 2nd December 1805, Napoleon won the crushing victory over Austria and Russia at Austerlitz and both were forced to sue for peace on Napoleon’s terms. These events effectively destroyed the Third Coalition and forced Austria and Russia out of active operations against the French. Prussia, which Napoleon had hoped to tempt with the offer of Hanover, had forces along the Ems and soon drew up its own accord with France – but less than a year later Napoleon defeated the Prussians at Jena-Auerstadt (October 1806) and the French occupation of Hanover resumed.

Part of the Parade Ground of the KGL at Bexhill
As a result of the collapse of the coalition, the small British army on the Weser found itself isolated with no hope of continuing meaningful operations and “greatly disappointed at having nothing to do”. All British forces were ordered home from Hanover in January 1806; the British HQ was moved to Osterholz early in February, then to Bremerlehe, and embarkation via Cuxhaven was completed by 12th Februar. It had by no means been a glorious or successful campaign – but that was not the fault of the KGL. Interestingly, the KGL was sent home first since it was feared that the Prussians would block their removal to England – there had been some hint already that Prussia wanted what was essentially a German force to conscript into its own army.
Embarked for UK under Cathcart Jan/Feb. 1806:
1st Heavy Dragoons KGL
2nd Heavy Dragoons KGL
1st Light Dragoons KGL
3rd Light Dragoons KGL
1st Light Battalion KGL
2nd Light Battalion KGL
1st Line Battalion, KGL
2nd Line Battalion KGL
3rd Line Battalion KGL
4th Line Battalion KGL
5th Line Battalion KGL
6th Line Battalion KGL
7th Line Battalion KGL
1/Coldstream Guards
1/3rd Guards
1/3rd Foot
1/4th Foot
1/5th Foot (5 Coys)
1/8th Foot
1/9th Foot
1/14th Foot
1/23rd Fuslrs.
1/26th Foot t (5 coys)
2/27th Foot (6 coys)
1/28th Foot
1/30th Foot
1/34th Foot
1/36th Foot
1/89th Foot
1/91st Foot
1/95th Rifles (4 coys)
Royal Artillery and KGL Artillery
Detachments of Royal Engineers and Waggon Train.
[this amounted to approx. 12,000 KGL and 14,500 British troops]
The KGL arrived in Portsmouth in the middle of February 1806, with the 1st Heavy and 1st Light Cavalry, the two Light Infantry battalions and the first two Line Brigades (i.e. four infantry battalions) being sent immediately to Ireland. By this time, a second regiment of Heavy Dragoons and another two of Hussars had been raised and a Fifth, Sixth and Seventh regiment of Line Infantry established, with an Eighth in formation.

KGL cemetery on “Barracks Rd.”, Bexhill.
Bases mid 1806 after return from Hanover:
Main training and recruit depot – Bexhill-on-Sea
1st Dragoons – Gort (Galway)
2nd Dragoons – Northampton
1st Hussars – Tullamore, Ireland
2nd Hussars – Canterbury
3rd Hussars – Guildford
1st Light Infantry – Bandon, Ireland, then at Tullamore
2nd Light Infantry – Bandon, Ireland, then Killbeggan, Westmeath.
1st Line Battn. – Kinsale, Cork [ordered to Gibraltar]
2nd Line Battn. – Middleton, Ireland [ordered to Gibraltar]
3rd and 4th Line – barracks at Colonooney, near Birr, Ireland.
5th, 6th, 7th, 8th Line Battalions – Winchester
Artillery – at Porchester.

Records of an arduous and honourable service – the 1841 Hanoverian Medal for the KGL, British MGS and Waterloo to 1st Hussars, KGL.

Waterloo Medal to QM H. Gropp, 2nd Dragoons KGL. An experienced cavalryman of the old Hanoverian Army when he joined the KGL, he served throughout the Peninsular War and was 54 years old at Waterloo!
As is well-known, the KGL went on to great things. Its units served in every theatre of war between 1806 – 1815, and often with great distinction – in the Baltic, Copenhagen, Sicily, Southern Italy and the Mediterranean, Walcheren and Holland, in N.E. Spain, Northern Germany and most notably throughout the Peninsular War in Portugal and Spain and into Southern France between 1808-1814; it was present in strength at Quatre Bras and Waterloo during the ‘Belgian’ campaign of 1815.
After a spell with the occupation forces around Paris and in northern France, the Legion was sent home to Hanover be disbanded in 1816, with many of its men having been away from their families and work for years. Many are known to have stayed in military service after 1816 and to have joined the reformed Hanoverian state army and some went on to achive high rank.
Their eventual battle-honours reflect their extensive service:
Horse Artillery – Göhrde [Elbe, 1814], Waterloo
Foot Artillery – Peninsula, Waterloo
1st and 2nd Heavy (later Light) Dragoons – Garcia Hernandez, Peninsula, Waterloo
1st Hussars – El Bodon, Peninsula, Waterloo
2nd Hussars – Barrosa, Peninsula
3rd Hussars – Peninsula, Göhrde, Waterloo
1st and 2nd Light Battalions – Venta del Pozo, Peninsula, Waterloo
1st, 2nd, 4th, 5th Line – Peninsula, Waterloo
3rd and 8th Line – Waterloo
6th and 7th Line – Peninsula
Some Hanoverian descendant regiments, and their Prussian and later Imperial German reflections, carried the old KGL battle-honours, like Peninsula, Garcia Hernandez, Venta del Pozo, Göhrde and Waterloo, into more modern times.

Memories of former KGL service – Hanoverian State artillery helmet plate of 1914-18 carrying the PENINSULA – WATERLOO – GOHRDE battle honours of its KGL artillery predecessor
Books:
Information on the KGL of course turns up in many sources on the Napoleonic Wars, its campaigns and battles.
The best English account is the excellent and detailed study by N. Ludlow Beamish – History of the King’s German Legion, 2 Vols., 1832-37, recently reprinted by Naval and Military Press.
Bernhard Schwertfeger – Geschichte der Königlich Deutschen Legion, 1803-16, 1907. A much quoted and referenced study.
Jens Mastnak – Die King’s German Legion, 1803-16, Celle 2015. An excellent modern study in German.
Jens Mastnak & M-A Tanzer: Diese denckwürdige under morderische Schlacht: Die Hannoveraner bei Waterloo, Bomann Museum, Celle, 2003. An account of both the KGL and Hanoverian forces in the Waterloo campaign.
Ludwig von Wissel – Ruhmwürdige Thaten welche in den letzten Kriegen von der Englisch-Deutschen Legion … verrichtet sind“, 1846. The original (very) detailed study in German of the awards of the Guelphic Medal, with their details, along with other “Ruhmwürdige Thaten” which were deemed worthy of note but didn’t merit the medal. Recently reprinted in paperback.
Bexhill Hanoverian Study Group – The King’s German Legion: From Bexhill to Waterloo, Bexhill Museum, 2003. An interesting series of articles on the links between the town and the KGL and modern survivals.
Various brief but useful Osprey books on the KGL.