In the following century, the Villa di Poggio a Caiano was used by successive Medici Grand Dukes of Tuscany. In 1587, Bianca Cappello and Francesco I de' Medici, Grand Duke of Tuscany died there within a day of one another after short illnesses; raising the still unsolved question of their poisoning by Francesco’s brother Ferdinand, who succeeded Francesco as Ferdinando I de' Medici, Grand Duke of Tuscany.[6] In the 17th and 18th centuries, the architects Giuseppe and Giovan Battista Ruggeri and Antonio Maria Ferri extended the villa.