The Battle of Crogen took place in the Ceiriog Valley, Wales in 1165, between the vanguard of the forces of Henry II of England and an alliance of Welsh princes led by Owain Gwynedd. Although outnumbered, the ambush tactics and valour of the Welsh aided them in their defeat of King Henry's army. Some sources report that adverse weather conditions also played a major part in Henry's defeat. Those weather conditions however were endured by both sides.