He was also made lord of Trapani, Agrigento, Bivona, Licata, Castronovo, Lentini, Palma di Montechiaro and Mussomeli, where he built a castle which still bears his name.
Manfredi was governor of Messina, and, after having liberated the island of Jerba from Arab pirates, he was made also lord of it.
Despite having obtained his lands by the Aragonese Kings of Sicily, he usually sided for the Angevines who held the rival Kingdom of Naples.
At the death of king Frederick III, Manfredi became one of four viceroys, ruling the kingdom for Maria, Queen of Sicily.
With the fall of the family from power, his daughter Costanza was divorced by the King Ladislaus and forced to marry a local Neapolitan noble.