When introducing himself to the class, young Merlin gives his name as "Mertin Ambrosius Caledonensis". The first name is, of course, a sly play on "Merlin" he made up on the spot, but other two names are derived from names used to refer to the wizard Merlin in the legend of King Arthur and stories that inspired the character. Merlinus Caledonensis is another name for the Welsh folk character Myrddin Wyllt (the name means "of town of Carmarthen", a place in South Wales,) while Merlin Ambrosius is the given name of the Merlin character in the original Arthurian story Historia Regum Britanniae by
Geoffrey of Monmouth.