 After his return he converted to Catholicism and became "Generalfeldwachtmeister" (equivalent to major-general) in the Austrian Army in 1692, at the age of 23.Then he fought against the French in the Nine Years' War.In 1695 he was sent by the Emperor to Spain at the head of an army-unit of 2,000 German soldiers to help defend Catalonia against superior French army and navy forces.