Constantine II was a Roman Emperor who ruled from 337 to 340 AD. He was the son of Constantine the Great, the first Roman emperor to convert to Christianity. After his father's death, Constantine II inherited the western part of the Roman Empire, which included territories in Europe and North Africa. During his reign, Constantine II faced challenges from his brothers, Constantius II and Constans, who ruled other parts of the empire. He is known for his military campaigns against the Picts in Britain and for his efforts to consolidate power. His reign ended when he was killed in battle against Constans.