What was the name of the Sorcerer in the Disney film 'Fantasia'?

Yen Sid is the powerful sorcerer in Fantasia, appearing as an old man with a long beard and robes that extended to the floor. The nickname ("Disney" spelled backwards) was given by Disney animators, as the sorcerer in "The Sorcerer's Apprentice" segment of Fantasia had no onscreen name, nor does the character in the original Goethe poem "Der Zauberlehrling", the inspiration for the music piece by Paul Dukas. Film historians believed Fred Moore added the same sized nose as Walt Disney's nose, and even added the same eyebrow length as Walt Disney's eyebrows; the animators used Disney's "dirty look" (which was the look that Walt gave his animators when he disapproved of their work) for the sorcerer by lifting his eyebrow.

Yen Sid serves as the sorcerer under whom Mickey Mouse is an apprentice. After executing a series of spells of summoning light out of a skull, changing its appearance as Mickey witnessed it while in the middle of his chores, Yen Sid decides to take a rest and he leaves his hat behind. From there, Mickey takes the hat and uses its magic to bring a broom to life to finish the chore of bringing water in from the well. However, Mickey does not know how to stop the magic now that it has been activated, and after he falls asleep, the entire basement is flooded. Thankfully, Yen Sid reappears, and uses his innate magical powers to recede the waters and undo the spell that caused the problem in the first place.