Pedro Fróilaz de Traba (fl. 1086–1126) was the most powerful secular magnate in the Kingdom of Galicia during the first quarter of the twelfth century. According to the Historia compostelana, he was "spirited ... warlike ... of great power ... a man who feared God and hated iniquity," for Diego Gelmírez himself had "fed him, like a spiritual son, with the nutriment of holy teaching." Brought up at the court of the Emperor Alfonso VI, Pedro raised the future Emperor Alfonso VII in his household. Around the latter he and Diego formed a "Galician party" that dominated that region during the turbulent reign of Urraca (1109–26). In September 1111 they even had the child Alfonso crowned king at Santiago de Compostela, but it was Pedro who was imperator in orbe Galletiae ("emperor in the ambit of Galicia").
Widely travelled and well-connected, especially through the prestigious marriages of his many daughters—he had at least sixteen legitimate children by his two wives—Pedro was, besides a political and military figure, a religious one. Sometime before 1109 he founded the first religious house for women in Galicia. As a result of his generosity to the Cathedral of Saint James in Compostela, Pedro is the best known Spanish nobleman of his era. One modern historian has written that he "needs a modern biography, and the materials are adequate for one." Most existing coverage is outdated or too heavily reliant on the Historia compostelana.
Pedro was the son of Froila Vermúdez de Traba and his wife, Elvira de Faro. The first reference to Pedro is from 9 November 1086, when he subscribed to his father's donation to the monastery of San Martín de Jubia, now Couto. According to the Historia compostelana, Pedro was raised from childhood at the court of Alfonso VI of León. His first wife was Urraca Fróilaz, daughter of Froila Arias and Ardio Díaz. They were married sometime before 12 August 1088, although a document surviving only in an eighteenth-century copy records their marriage on 11 August 1102. By 6 May 1105 Pedro had remarried to Mayor (Guntroda) Rodríguez (de Bárcena), daughter of Rodrigo Muñoz. Mayor was a major benefactress of Lugo Cathedral (14 June 1112) and the monasteries of Jubia (26 December 1114) and Sahagún (26 March 1125). She is last recorded alive on 6 January 1129 and probably died not long afterwards.