Saint Gorboduc was a Visigoth living in the Seventh Century who was murdered by his cousin, Harg (Saint Fidgeta and Other Parodies; 33). Harg later began building the Cathedral of Saint Gorboduc on the spot where he murdered his cousin.
Gorboduc was a legendary king of the Britons who was the subject of the 1561 play, Gorboduc. The play is historically important for being the model for later Elizabethan drama and as the first play written throughout in blank verse. “It was the first blank-verse tragedy in English and one of those things that all English majors (or at least graduate English majors) learn about. John obviously liked the sound of the name, and perhaps thought of it as an in-joke for English majors." It is assumed from that comment Bellairs heard of the play from his graduate studies in Chicago.
"A niece of King Gorboduc" is mentioned briefly by the Fool in Shakespeare's Twelfth Night.