 In January 1090 Pedro was governing Ferreira in Galicia and is described in a royal charter as "dominator Ferrarie" (lord of Ferreira, today part of Coristanco).The only contemporary reference to Pedro which names him in the way by which he is now generally known is an undated fragment of a charter of Alfonso VI, which calls him "Petro Froillaz de Traua".It was the thirteenth-century historian Rodrigo Jiménez de Rada some hundred years later who initiated the historiographic tradition, still followed today, which names Pedro and his descendants "de Traba".