Cosimo III de' Medici, Grand Duke of Tuscany
Maria Anna Josepha died in 1689 of tuberculosis. A couple of years later, on 29 April 1691, Johann Wilhelm married by proxy Anna Maria Luisa de' Medici, daughter of Cosimo III de' Medici, Grand Duke of Tuscany. She departed for Düsseldorf on 6 May 1691, accompanied by her younger brother, Gian Gastone. Johann Wilhelm surprised her at Innsbruck, where they officially married.