According to tradition, young Giacomo was ploughing a field when mercenaries led by Boldrino da Panicale passed nearby in search of recruits.
[2] In 1398 he was at the service of Perugia against the Milanese troops of Gian Galeazzo Visconti, to whom Muzio soon switched his loyalty following the typical behaviour of mercenary chieftains of the time.
In the following, confused, events that led to the arrival of Louis III of Anjou in Naples in opposition to Alfonso V of Aragon, Sforza helped Joan and Sergianni to flee to Aversa.
They had: On 16 June 1413, Sforza married secondly with Caterina (also named Catella; died 1418 in childbirth),[5] a sister of Pandolfello Piscopo "Alopo", Grand Chamberlain of the Kingdom of Naples and lover of Queen Joanna II.
They had: In 1421, Sforza married thirdly with Maria (died 1440),[5] daughter of Giacomo da Marzano, 1st Duke of Sessa, and Sovereign Countess of Celano after inheriting from her first husband Nicola de Berardi.