His origins are obscure, but he was probably a member of the Vela family, a brother of count Bermudo Núñez, and thus uncle of Fernando Bermúdez de Cea, who is known to have inherited property from Oveco.
[4][5] Oveco witnessed three different donations to the monastery of Sahagún in 945, his name being recorded three different ways: Ovecco Munniz, Obeco Muniz, and Ovecus episcopus.
Around 937, Oveco led an expedition with his brother Vermudo to the region around of Salamanca, there to found new villages (repoblación) and consecrate new churches with the newly appointed bishop, Dulcidio II.
[6] In 953 Ordoño III donated all the settlements and churches founded by Oveco and his fellows to the diocese of León.
[7] Oveco founded a monastery in Vega, which passed to his nephew Fernando on his death.