Chancellor Galder Weatherwax was a chancellor of Unseen University. He was originally titled Chancellor, but was upgraded to Archchancellor by Mustrum Ridcully. . He was the 304th Archchancellor of the Unseen University and was described by Esmerelda "Granny" Weatherwax as "a distant cousin; never met him." His full title is "Supreme Grand Conjurer of the Ancient and Truly Original Brothers of the Silver Star, Lord Imperial of the Sacred Staff, Eight-Level Ipsissimus".
It is believed that while he was cunning and watchful enough to ward off most assassination attempts by ambitious seventh-level Mages (especially Ymper Trymon), his foresight failed in matters relating to interior design, in that he commissioned a bathroom from Bergholt Stuttley Johnson without stopping to ask what might, on the basis of B.S. Johnson's past form, possibly go wrong. More is revealed about Archchancellor Weatherwax's bathroom in 'Hogfather', when a later Archchancellor (Ridcully) discovers the fixture, and rather rashly has it set up for use. Again displaying uncharacteristic naivety about his fellow wizards, Weatherwax apparently survived his encounter with the bathroom, at least for long enough to nail up the door and put up a notice along the lines of "Never, ever, use again".
His tenure as Archchancellor comes to an end during The Light Fantastic when he is eaten - having mistakenly summoned The Luggage instead of Rincewind - paving the way for Trymon to become Archchancellor. in the film adaptation he is pushed to his death by Ymper Trymon.
James Cosmo of Highlander and Braveheart fame played Galder Weatherwax in the Sky One adaptation of The Colour of Magic.