The Gesta Episcoporum Neapolitanorum records that "Sergium filium Marini et Eupraxiæ" defended Naples against the invasion of Sicard Prince of Benevento, dated to 835.
Count of the castle of Cuma. He was chosen by the Neapolitans as their leader and established himself in 840 as SERGIUS I Duke of Naples. The Chronicon Ducum…Neapolis records that "Sergius" succeeded "19 anno tertia ind" and ruled 25 years and 3 months. An Arab fleet occupied the island of Ponza in [842], but was driven off by Duke Sergius in alliance with Gaeta, Amalfi and Sorrento.
Married Drosu, daughter of ---. The Vita Athanasii Episcopi Neapolitani names "Drosu, principali propagine satam" as wife of Duke Sergius. The Gesta Episcoporum Neapolitanorum records that "Sergius dux Neapolitano…et uxoris eius Drusu" donated "velamen cum auro et gemmis atque listis ornatum" to the see of Naples. 1
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