For some years now, we have been witnessing politicians of all ideologies and nationalities trivializing the political, social and ideological processes associated to the Middle Ages. The messages launched from these positions of power have been often accepted without questioning their reliability. In Zamora (Spain), in a plenary session held on 24th June 2009, the City Council decided to change the name of the “Gate of Betrayal” of the city’s castle grounds to “Gate of Loyalty”. This action sought to vindicate the figure of Vellido Dolfos, now presented as the liberator of the city, rather than as a medieval traitor—which is how some medieval sources describe him. This name change has wider implications, as it alters the narrative of a significant episode in the medieval history of the kingdoms of León and Castile: the assassination of King Sancho II of Castile at the hands of the aforementioned Vellido Dolfos in 1072. Did the political party that suggested such a change provide an accurate historical argument? Was this an attempt to re-assess history, or was it, in reality, a crude political manoeuvre to gain political notoriety, albeit at local and regional levels? This paper will answer these questions by critically reviewing the existing evidence concerning Vellido Dolfos and his ‘myth’.