Gian Galeazzo Visconti
The Duchy of Milan "(Ducatus Mediolani)" as a state of the Holy Roman Empire was created on 1 May 1395, when Gian Galeazzo Visconti, purchased a diploma for 100,000 Florins from King Wenceslaus. It was this diploma that installed Visconti as Duke of Milan and Count of Pavia.