He also received the seigniory of other cities of the duchy, including Lodi, and started to carefully plan the conquest of the ephemeral republic, allying with William VIII of Montferrat and (again) Venice. In 1450, after years of famine, riots raged in the streets of Milan and the city's senate decided to entrust to him the duchy. Sforza entered the city as Duke on 26 February. It was the first time that such a title was handed over by a lay institution. While the other Italian states gradually recognized Sforza as the legitimate Duke of Milan, he was never able to obtain official investiture from the Holy Roman Emperor. That did not come to the Sforza Dukes until 1494, when Emperor Maximilian formally invested Francesco's son, Ludovico, as Duke of Milan.