What bank was founded by the great-great-great grandfather of the second Duke of Florence?
Giovanni di Bicci de' Medici:  He was the father of Cosimo de' Medici ("Pater Patriae"), grandfather of Piero di Cosimo de' Medici, great-grandfather of Lorenzo de' Medici (the Magnificent) and great-great-great-grandfather of Cosimo I de' Medici, Grand Duke of Tuscany.
i don't know