Aldobrandino I d'Este

Aldobrandino I d'Este (c. 1190–1215) succeeded his father Azzo VI in 1212 as Marquis of Este and lord of Ferrara. He backed Pope Innocent III and Frederick II against Otto IV.

War with Padua cost him Este and Montagnana in 1213, and after a surrender he returned to Ferrara and reached a compromise with the powerful Salinguerra family. At Innocent's bidding he campaigned in the March of Ancona against the Celano counts, initially defeating them.

He died at Ancona in October 1215, aged twenty-five, perhaps poisoned. His posthumous son Contardo was venerated as a saint, and his daughter Beatrice married Andrew II of Hungary.