This square was named in 1997, when the town celebrated the millennium of an act considered real and reflected in a historical romance in which the first four verses say:

Already kiss their wives
and embrace their children
fifty the knights
that came out of Uncastillo

Relates how Almanzor, a Muslim warlord, arrested in the year 994 to fifty knights of Uncastillo that in those days was in lands of the kingdom of Navarre. They took hostage to Cordova, under threat of killing them if the christians attacked any muslim place. But three years later, a Christian attack was the excuse for Muslims to murder the fifty knights of Uncastillo.