In March 976, he confirmed a donation made by his uncle count Fruela Vélaz to the Cathedral de Oviedo, as Gundimaro Pinioli armiger, that is, the standard-bearer of King Ramiro III of León.
[6] During a period of fifteen years he served in the curia regis of King Bermudo III of León and in March 996 appears for the first time with the title of count.
For his baptism, Queen Velasquita Ramírez, possibly his godmother, gave him real estate properties[7] He also owned land and villas in Teverga.
[8] With his wife Muniadona he made many donations to religious establishments, especially to the Monastery of San Vicente de Oviedo and to the city's cathedral.
They were the parents of: Gundemaro appears in 991 for the first time with his second wife Muniadona, whose parentage is unknown and who must have married at a very young age since she is still recorded as living in 1045.