Sergius, their father, allied with Landulf, the gastald of Suessola and Sessa [Note 1] and son of Lando I, Count of Capua.
In May that year, a massive joint expedition of Salerno, Naples, and Amalfi marched on Capua, led by Caesar and Gregory, and their brother-in-law of Suessola.
Erchempert places the battle on 8 May, the day of Michael the Archangel, whose cult was popular among the Lombards.
Sergius, before dying, bade his son to follow the counsel of his brother the bishop, who was a familiaris of the Emperor Louis II and a papal legate with connections in the Roman curia.
In 866, Gregory personally accompanied Louis against Capua, Salerno, and Amalfi.