6th was a regiment at the battle that involved which deposed English king?
6th (Inniskilling) Dragoons:  One of the regiment's most notable battles was the Battle of the Boyne in July 1690. Battle of the Boyne: The Battle of the Boyne (Irish: "Cath na Bóinne" ] ) was a battle in 1690 between the forces of the deposed King James II of England, and those of Dutch Prince William of Orange who, with his wife Mary II (his cousin and James's daughter), had acceded to the Crowns of England and Scotland in 1688.
i don't know