"Berenguela of Castile (1180-1246) was one of the most powerful women in Europe. As queen-consort of Alfonso IX of León, she acquired the troubled boundary lands between the kingdoms of Castile and León and forged alliances with powerful nobles on both sides. Even after her marriage was dissolved, she continued to strengthen these connections as a member of her father's court. On her brother's death, she inherited the Castilian throne outright—and then, remarkably, elevated her son to kingship at the same time. Using her assiduously cultivated alliances, Berenguela ruled alongside Fernando and set into motion the strategy that in 1230 would result in his acquisition of the crown of León—and the permanent union of Castile and León." ~ Janna Bianchini (2010)
Bianchini, Janna (2010). The Queen's Hand: Power and Authority in the Reign of Berenguela of Castile. Project Muse.
Weis, Frederick Lewis, Ancestral Roots of Certain American Colonists who Came to America Before 1700, 7th ed., Baltimore MD: Genealogical Publishing Co., Inc., 1992. Access online (search only) at GoogleBooks, Line 114, pp. 104-105: m.Alfonso IX, d.1244; Line 120, p.107.
Roberts, Gary Boyd, The Royal Descents of 600 Immigrants. Baltimore, MD, USA: Genealogical Publishing Co., 2004; [database on-line] Ancestry.com, Provo, UT, USA: Ancestry.com Operations, Inc., 2006: #467 p.385-6.