The dynasty was founded by Francesco Sforza, who ruled Milan for the first half of the Renaissance era, acquiring the title of Duke from the extinct Visconti family in 1447. While there were many good rulers in the family, there were also a number of despots, many of which were mentally unstable.
This family would later join with the Borgia Family, through the arranged marriage of Lucrezia Borgia to Giovanni Sforza (who was the illegitimate son of Costanzo Sforza).
After the French were driven out by Swiss Mercenries, Maximilian Sforza, son of Ludovico became Duke of Milan, until the French returned under Francis I of France and imprisoned him.
Not to be confused with sforzando, a musical marking.