It takes a score card to keep the Maria Luisas straight. This particular Maria Luisa was Infanta of Spain, daughter of Carlos III, who married the future Holy Roman Emperor Leopold II. She moved from Spain into Habsburg lands in Tuscany and lived in Florence for 25 years beginning in 1765. She should not be confused with Maria Luisa of Parma who moved from Italy to Spain. This Maria Luisa's Wikipedia article is here.