Rudesind was born into the nobility: his father was Count Gutierre Menéndez (Latin: Gutiher Ermegildi), brother-in-law to Ordoño II and supporter of Alfonso III of León, and his mother was St. Ilduara Eriz (Latin: Hilduara Erici),[1][3] daughter of count Ero Fernández.

Rudesind was the grandson of Ermesenda Gatónez, sister of his predecessor in the see of Mondoñedo (Dumium), Bishop Sabarico II, and was also related to the abbess Saint Senorina.

Rudesind also had jurisdiction over the lands that extended from Riocaldo (the southern boundary of Galicia) to Santa Maria de Ortigueira (on the Cantabrian coast).

[3] Later, at the request of Elvira Ramírez of León (Latin: Geloyra Renamiri), aunt of the future Ramiro III, he was made governor of Galicia, from spring of 968 to early 969.

After the killing of Sisnand in the battle of Fornelos, Rudesind was appointed administrator of the See of Iria Flavia, and he was in charge of that diocese from 968 to 977.

As abbot of Celanova, he was a leading figure of his time, and received visits from religious leaders throughout Galicia and Portugal who wanted spiritual advice.