Despite being Holy Roman Emperor, Francis I was somewhat overshadowed by his wife, Maria Theresa, the Habsburg heiress, who he married in 1736. The following year he surrendered his duchy of Lorraine to help end the War of the Polish Succession. He was Maria Theresa's co-regent throughout the Wars of the Austrian Succession (1740-1748), and was Holy Roman Emperor during the Seven Years War, when he was again overshadowed by his wife.