The Conti di Marsi, the Counts of Marsi, were a lineage of Frankish origin who figured among the main feudal lords of Abruzzo, part of the Duchy of Spoleto in southern Italy, during the eleventh and twelfth centuries.
With Celano as their main seat, they ruled over a territory that stretched from Lake Fucino as far as the Peligni.
They descended from a certain Berardo who was called "Francesco" because he came from Francia, who came to Italy with Hugh of Provence, King of Italy from 924 until his death in 948. According to the Chronicle of Monte Cassino, the first known member of this family, Azzo, Berardo's uncle, was a Burgundian count. The conti di Marsi considered themselves Berardinga, "Berardings" or, by modern historians, Bosonids.
The chronicler of Monte Cassino who records this decisive event was of the house himself, Leo Marsicanus (1046, Marsica — 1115 or 1117, Ostia) (meaning "of the Marsi"), also known as Leone dei Conti di Marsi; Leo became a monk in Monte Cassino around 1061 and served as a cardinal in the early twelfth century.
As Azzo and Berardo arrived in Italy with Hugh in 926, it is likely that these Burgundian counts originated in the Kingdom of Arles, originally the southern part of the kingdom of Burgundy, where Hugh's family originated. Though the name Azzo is familiar today from the Este family, later rulers in Ferrara and Modena, the name was not unusual in northern Italy at the time.
The Lombard gastaldate of Marsi in the territory of the dukes of Spoleto was erected as a county by Louis the Pious.