Yes he was.
King Arthur was king of Britain
It is really not known if King Arthur was a Christian. The Catholic Church did have missionaries that were in Great Britain, so it is possible that he became one.
Britain
It's a folktale of how King Arthur became king of Britain.
Britain
King Arthur of Britain.
Britain.
panis
Right before King Arthur died, he passed on the throne to Constantine the Third of Britain.
The time of King Arthur (the real Arthur) to 1600
In the movie, Rome was retreating from Britain as the Goths? from France were invading. King Arthur was asked to leave to Rome also, but he chose to stay and try to protect Britain from foreign invaders. King Arthur had a Roman father and British mother so he felt some obligation to Britain.
Chiefly in Britain and France.