seed"), long identified with Benedictine monastery of Santo Domingo de Silos in Castile, based on a marginal note in the Fresdelval manuscript that read "Santo Domingo de Silos". This position was strongly defended by historian Justo Pérez de Urbel, himself a monk of Silos. The author's lack of interest in Castilian matters and his ignorance of Castilian geography, as well as the complete absence of Silos from the Historia, suggest another monastery, probably in León. The term domus seminis may derive from a misunderstanding of the abbreviation dms scis, which could have stood for Domnis Sanctis ("at the lord saints'"). The monastery of Sahagún, the most important monastery in León during the reign of Ferdinand I and which maintained close ties with the royal court, was often known as Domnis Sanctis on account of its dual dedication to Facundus and Primitivus. While Sahagún is mentioned three times in the Historia and Alfonso VI was buried there, neither this burial nor the abbacy at Sahagún of Bernard de Sedirac (1080–85) are mentioned in places where they would be expected. Another possible source for domus seminis was suggested in 1961 by the paleographer Manuel C. Díaz y Díaz. He suggested that it was a mistaken expansion of sci ihnis, in fact an abbreviation of sancti Iohannis, that is, Saint John's. A house in the city of León, with a community of monks dedicated to John the Baptist and one of nuns dedicated to Pelagius of Córdoba (San Pelayo), was founded in 965 by Sancho I of León and enjoyed royal patronage. Though it suffered several raids from Almanzor, it was restored by Alfonso V (999–1028) and patronised heavily by his daughter Sancha and her husband, Ferdinand I. In 1063 these monarchs had the relics of Isidore translated from Seville to Saint John's, which they refurbished and embellished. The house was thereafter known as San Isidoro de León (though the use of "Saints John and Isidore" for the male community is found in a diploma of Alfonso VI of 1099). The anonymous author, if sancti Iohannis was indeed his intention, may have sought to indicate that he became a monk at the monastery before 1063. He elsewhere refers to the church as hanc ecclesiam (this church), indicating perhaps his own locality and his intended audience (his brother monks). The author is sometimes known as the Monk of Silos, despite that this identification has