The Brandenburgisches Dragoner-Regiment Nummer 5 (Prinz Wilhelm) was formed on the 16th of October, 1807, from the 1st and 2nd squadrons of the old 5th von Balliodz Kürassiere Regiment and the depot, 2nd, 3rd and 4th squadrons of the old 1st Prince William Dragoon Regiment. It was thus regarded as a "new" regiment rather than one of the surviving "old" regiments.
In 1812 the 1st and 3rd squadrons were merged with squadrons from the 2nd (1st West Prussian) Dragoons and sent to Russia, as part of the Prussian force accompanying Napoleon on his invasion of Russia. The regiment saw minor action in the campaign and lost 1 officer, 34 men and 86 horses.
In 1813, with the declaration of war on France, the regiment saw far heavier fighting. Part of 1. Brigade, III Corps Reserve Cavalry, it was part of Bernadotte's Army of the North and saw action at Gröss Gorschen, Borna and Bautzen. The regiment was heavily engaged in the defeat of the French at Dennewitz. It is credited with riding over three French squares and a Württemberg square, a French battery (capturing four guns), routing a Polish Uhlan regiment and sharing the capture of 412 wagons and 4 (some sources say 7) flags with the 2nd Dragoons and 1st Pommeranian Landwehr Cavalry. But the unit paid a price, losing 7 officers, 88 men and 156 horses.
In 1814 the regiment was present at Oudenarde, Antwerp, Soisson and Laon.
1815 saw the regiment as part of the cavalry reserve of I Korps, fighting in Belgium and France. At Villers-Cotterets the regiment caught the fleeing French and captured 3 guns, a howitzer and 22 munitions wagons.
The regiment was awarded the following decorations for its service in the Napoleonic Wars:
The Brandenburgisches Infanterie-Regiment Nummer 12 was formed on the 1st day of July, 1813. The regiment was formed from the 1st and 2nd Reserve battalions of the Leib-Infanerie-Regiment and the 3rd Reserve battalion of the 1st Westpreußisches Infanterie-Regiment. It was raised to fill in the vacant position in the army lists that was caused when the Garde-Infanterie-Regiment was removed from the line numbering and the infantry regiments numbered 9 to 12 became 8 to 11. It therefore is very similar to the Reserve-Infanterie-Regimenter raised at the same time, but was always considered a part of the line rather than as an ad-hoc formation. It wasn't called the "2. Brandenburgisches IR" until 1823.
The regiment varied from the other line units in that it had no grenadier companies. However, the usual organisation of three battalions (two musketeer and one fusilier, or light, battalion) was the same as the other infantry regiments. The regiment had no colours until 3 September 1815, when new colours were presented to the unit in France.
The regiment saw action at Lowenberg and Colberg before being part of Blücher's force that defeated MacDonald at the Katzbach. The 2nd battalion was credited with capturing an eagle and 188 French troops, after attacking a French square, in this action. It later took part in all the actions of 1813, being present at Bishofswerda, Wartenburg and Möckern as part of 8 Brigade, I Corps from Augst 1813. In 1814 the regiment was at Château-Thierry, Laon, and eventually the entry into Paris.
In 1815 was the regiment was part of 1. Brigade, I Korps and saw action in the battles of June, 1815, before advancing on Paris to force Napoleon's final abdication.
For its service the unit was awarded the following decorations:
Formed from reserve battalions, the unit wore a number of different uniforms in its ranks. Illustrated below is that of the 1st Battalion (from Knötel's Uniformekunde).
The regiment went on to give distinguished service, being re-titled as a grenadier regiment in 1861 and finally being disbanded in 1919.