Aurelian came to be Duke by way of inheritance, as his wife Guena was the daughter of the previous Duke. He ruled over Varuz at a time of great chaos, spending much of his reign dealing with the impending invasion of a neighbouring nation's Duke, Conrad. Despite the protests of many of his allies and advisors - including his close friend Lord Bernhardt, his nephew-in-law Mikhail, and the Twelfth Doctor - Aurelian refused to surrender to Conrad's advances, or to negotiate a peace treaty for Varuz. As a result of his stubornness, many of Aurelian's court worked against him in secrecy; Bernhardt and Guena, who were romantically involved, enlisted both Clara Oswald and Mikhail in their plan to secretly negotiate peace with Conrad. When Aurelian discovered this plot, he banished Clara and Mikhail, along with Emfil, from Varuz.
Following Lancelot's arrival in Varuz, Aurelian became enamoured with the idea of tracking down the Holy Grail, and sent many of his knights away with Lancelot on a quest to retrieve it. This quest never came to fruitition, and Guena was eventually able to persuade him to recall his knights.
When Conrad's army reached Varuz, Aurelian marched his army into battle in a desperate attempt to protect his homeland from invasion. He was slain by Mikhail, who had turned traitor against him. (PROSE: Royal Blood)