 On 20 December 1807 he was given the title of "Prince de Venise" ("Prince of Venice"), a title created on 30 March 1806, when the Venetian Province taken from Austria in 1805 was united to Bonaparte's Kingdom of Italy.In 1810, Napoleon used his influence over Karl von Dalberg, Archbishop of Regensburg and Grand Duke of Frankfurt, to name Eugène as constitutional heir of the grand duchy.Von Dalberg abdicated on 26 October 1813 due to Frankfurt's imminent conquest by the allied armies, and Eugène became nominal grand duke until Frankfurt was occupied by the allies in December of that same year.