In September 1636 Leslie and the imperialists were defeated by the French, the Swedes and Saxe-Weimar at the Battle of Wittstock. However, in 1637, Leslie wrote to the dying Ferdinand II, making his argument that he had Habsburg blood dating back over half of a century. After Ferdinand II's death, Ferdinand III approved the request and ennobled Leslie as an Imperial Count. This new title brought with it a new lifestyle, new political respect and more diplomatic opportunities. Leslie served as a Stuart-Habsburg intermediary at the Ratisbon Electoral meeting (1636–43), Imperial envoy to the Spanish Netherlands (1639), diplomatic trips to the Caroline Court in Spain, delegate in Regensburg (1640), and ambassador to Naples in 1645. In 1645, Leslie, then Imperial Ambassador to Naples, roamed the Italian Peninsula in an attempt to garner funds to fight the war. He is reported to have given Pope Innocent X a solid silver writing table. The trip yielded little money and few troops.