- William of Peñacorada
Monk in Sahagún, León, Spain. He and his brothers fled from there ahead of invading Saracens, and settled in Peñacorada, Spain. Built the monastery of Santa Maria de los Valles, which was later renamed San Guillermo de Peñacorada in his honour.
- Book of Saints, by the Monks of Ramsgate
- Catholic Online
- Our Sunday Visitor’s Encyclopedia of Saints
- “Saint Guillermo de Peñacorada“. CatholicSaints.Info. 20 March 2010. Web. 28 August 2016. <>