Otto was the mayor of the palace

Mayor of the Palace

Mayor of the Palace was an early medieval title and office, also called majordomo, from the Latin title maior domus , used most notably in the Frankish kingdoms in the 7th and 8th centuries....

 of Austrasia

Austrasia

Austrasia formed the northeastern portion of the Kingdom of the Merovingian Franks, comprising parts of the territory of present-day eastern France, western Germany, Belgium, Luxembourg and the Netherlands. Metz served as its capital, although some Austrasian kings ruled from Rheims, Trier, and...

 briefly in the mid-seventh century.

Otto was the son of a domesticus

Domesticus (Roman Empire)

A domesticus was a member of the protectores domestici, an elite guard unit of the Late Roman army, who served as bodyguards and staff officers to the emperor. As its name testifies, these were troops considered as belonging to the household of the emperor...

named Uro who served in the court of Dagobert I

Dagobert I

Dagobert I was the king of Austrasia , king of all the Franks , and king of Neustria and Burgundy . He was the last Merovingian dynast to wield any real royal power...

. Otto was raised with Dagobert's son Sigebert III

Sigebert III

Sigebert III was the king of Austrasia from 634 to his death; probably on 1 February 656, or maybe as late as 660. He was the eldest son of Dagobert I....

 and subsequently acted as Sigebert III's baiolos (bailiff

Bailiff

A bailiff is a governor or custodian ; a legal officer to whom some degree of authority, care or jurisdiction is committed...

?). On the death of Pepin of Landen in 639 or 640, Otto challenged the succession of Grimoald to the mayorship. Otto was eventually murdered by Leuthard II, Duke of Alemannia, at the request of Grimoald.

Sources

• Hummer, Hans J. Politics and Power in Early Medieval Europe. Cambridge University Press: 2005.