Sergius III (died November 1073) was the duke of Amalfi from 1069, when he succeeded his father John II

John II of Amalfi

John II was the duke of Amalfi from 1029 to 1069 with multiple interruptions. He was the son of Sergius II and Maria, sister of Pandulf IV of Capua. He was the last significant duke of Amalfi before the Norman conquest of 1073....

, until his death. He was first appointed co-regent by his father in 1031. He and his father were expelled from Amalfi

Amalfi

Amalfi is a town and comune in the province of Salerno, in the region of Campania, Italy, on the Gulf of Salerno, c. 35 km southeast of Naples. It lies at the mouth of a deep ravine, at the foot of Monte Cerreto , surrounded by dramatic cliffs and coastal scenery...

 by his grandmother and uncle, Maria

Maria of Amalfi

Maria was one of the two daughters of Pandulf II of Benevento, who was also Pandulf III of Capua. She married Sergius II of Amalfi around 26 April 1002. Her sister Gaitelgrima married Guaimar III of Salerno, while her brothers, Landulf and Pandulf, became princes respectively of Benevento and...

 and Manso II

Manso II of Amalfi

Manso II the Blind was the duke of Amalfi on three separate occasions: from 1028 to 1029, from 1034 to 1038, and from 1043 to 1052. He was the second son of Sergius II and Maria, sister of Pandulf IV of Capua. His whole ducal career consisted of wars with his brother, John II, over the throne. The...

, in April or May 1034.

In 1038, he returned with his father from exile in Naples

Naples

Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...

, but they were forced out again the next year by Guaimar IV of Salerno

Guaimar IV of Salerno

Guaimar IV was Prince of Salerno , Duke of Amalfi , Duke of Gaeta , and Prince of Capua in Southern Italy over the period from 1027 to 1052. He was an important figure in the final phase of Byzantine authority in the Mezzogiorno and the commencement of Norman power...

. In 1052, they returned from an exile in Greece

Greece

Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

 after Guaimar's assassination. The remaining years of John II's rule were peaceful except in regards to his relations with Gisulf II of Salerno

Gisulf II of Salerno

Gisulf II was the last Lombard prince of Salerno ....

, Guaimar's successor. Gisulf eventually made peace with John, but war broke out between Amalfi and Salerno

Principality of Salerno

The Lombard Principality of Salerno was a South Italian state, centered on the port city of Salerno, formed in 851 out of the Principality of Benevento after a decade-long civil war....

 on John's death. In 1071, Sergius (now sole ruler) was at Montecassino for the reconsecration of that great abbey. Gisulf was also present and Pope Alexander II

Pope Alexander II

Pope Alexander II , born Anselmo da Baggio, was Pope from 1061 to 1073.He was born in Milan. As bishop of Lucca he had been an energetic coadjutor with Hildebrand of Sovana in endeavouring to suppress simony, and to enforce the celibacy of the clergy...

 worked out a peace between the two rulers. It lasted until Sergius' death in late 1073. He was succeeded by his infant son John III

John III of Amalfi

John III or John IV was the duke of Amalfi briefly in 1073 by right of succession following the death of his father, Sergius III, in November. John was only an infant when his father died, The Amalfitans, who required a ruler who could defend them, quickly deposed and exiled him...

, who was soon deposed. Sergius is thus the last independent duke of Amalfi.