The Gesta Episcoporum Neapolitanorum records that "Gregorius dux" shared power with "consulem Sergium filium suum", with the advice of "suis germanis".
He succeeded as prefect of Amalfi in 866 on the assassination of prefect Mauro, but only remained as prefect for 13 days. He succeeded his father in 870 as SERGIUS II Duke of Naples. The Gesta Episcoporum Neapolitanorum records that "Sergius consul" arrested "omnes germanos patris sui" after his father died. The Chronicon Ducum…Neapolis records that "Sergius" succeeded Duke Gregorius (without specifying the relationship between the two) "tertio an 3 ind" and ruled 7 years and 6 months. He made an alliance with the Aghlabids of Sicily after his succession, which was opposed by his uncles Cesarius and Athanasius. Erchempert records that "Sergius" was captured by "proprio germano", blinded, and exiled to Rome, dated to 878.
The name of Duke Sergius's wife is not known. 1
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