William Windsor (known as Billy), a goat in the military, was a lance corporal in the 1st Battalion, the Royal Welsh, an infantry battalion of the British Army. He served as a lance corporal from 2001 until 2009, except for a three month period in 2006 when he was demoted to fusilier, after unacceptable behaviour during the Queens' birthday celebrations while deployed on active service with the battalion on Cyprus. He retired to Whipsnade Zoo in May 2009.
The tradition of having goats in the military originated in 1775 when a wild goat walked onto the battlefield in Boston during the American Revolutionary War and led the Welsh regimental colours at the end of the Battle of Bunker Hill.
Billy, a Kashmir goat from the royal herd at Whipsnade Zoo, was presented to the regiment by Queen Elizabeth II in 2001. He is said to be friendly and likes meeting people. The tradition is not new: since 1844, the British Monarchy has presented an unbroken series of Kashmir goats to the Royal Welch Fusiliers from the crown's own royal herd.
The royal goat herd was originally obtained from Mohammad Shah Qajar, Shah of Persia from 1834–1848, when he presented them to Queen Victoria as a gift in 1837 upon her accession to the throne. Billy is thus descended from the same royal bloodline as the original herd.