Sir Bedivere stayed loyal to King Arthur throughout his life. Among other quests, he helped Arthur and Sir Kay fight the Giant of Mont St. Michel. Bedivere and King Arthur were among the few surivors of the Battle of Camlann. After the battle, at the request of the mortally wounded king, Bedivere threw Excalibur back to the Lady of the Lake. He then entered a hermitage where he spent the remainder of his life.
His tales are some of the oldest among those of King Arthur. Because he was mentioned in older stories, it is possible that he might have really lived.
His name in Welsh is Bedwyr Bedrydant (Bedivere of the Perfect Sinews). Stories described him as one handed yet still a very capable warrior.