The Battle of Salamanca, 22nd July 1812, was arguably the decisive engagement of the Peninsular War. Within the space of a few hours the British and allied forces commanded by the Duke of Wellington soundly defeated a similiar sized French army under Marshal Marmont. The battle was a turning point in the Peninsular War with Wellington finally going on the offensive; some consider it to have been Wellington's finest hour.
The Imperial Eagle, the battle standard of the French 62nd Line (Thomières), was captured by Lieutenant Pearce of the 44th East Essex Regiment. The lineage of the 44th transferred to the Essex Regiment in 1881 and subsequently by a series of amalgamations and restructures to the 1st Battalion of the Royal Anglian Regiment.
Happy Salamanca Day!
British Battles: the Battle of Salamanca
Wikipedia: Battle of Salamanca