John IV (died April or August 1012) was the eldest son of

John III of Gaeta John III (died 1008 or 1009) was the consul and duke of Gaeta from some time between October 984 and January 986 until his death. He was the eldest son of Marinus II, who succeeded his brother Gregory in 978 and immediately appointed John as co-d ...

who was appointed co-duke in 991 while still young (he was a minor even in 994). John succeeded his father in 1008 or 1009 and ruled for a brief four years. John married Sichelgaita, daughter of

John IV of Naples John IV was the mostly absentee duke of Naples from 997 to after 1002. He was the son and successor of Sergius III. John IV originally recognised the suzerainty of the Byzantine Emperor. In 999, he was captured and taken a prisoner first to Cap ...

and sister of Sergius IV. He left an infant, perhaps posthumous, son under the

regency A regent (from Latin : ruling, governing) is a person appointed to govern a state '' pro tempore'' (Latin: 'for the time being') because the monarch is a minor, absent, incapacitated or unable to discharge the powers and duties of the monarchy ...

of his mother,

Emilia Emilia may refer to: People * Emilia (given name), list of people with this name Places * Emilia (region), a historical region of Italy. Reggio, Emilia * Emilia-Romagna, an administrative region in Italy, including the historical regions of Emi ...

. His brother Leo fought for the regency and his cousin Leo tried to usurp the throne from the young John V.

Sources

*Caravale, Mario (ed). ''Dizionario Biografico degli Italiani LV Ginammi – Giovanni da Crema''.

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus (legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

, 2000. 10th-century births 1012 deaths Dukes of Gaeta {{Italy-noble-stub