Ferdinand I of Leon was the leading king of the mid-11th century. He conquered Coimbra and attacked the taifa kingdoms, often demanding the tributes known as parias. Ferdinand's strategy was to continue to demand parias until the taifa was greatly weakened both militarily and financially. He also repopulated the Borders with numerous "fueros". Following the Navarrese tradition, on his death in 1064 he divided his kingdom between his sons. His son Sancho II of Castile wanted to reunite the kingdom of his father and attacked his brothers, with a young noble at his side: Rodrigo Díaz, later known as El Cid Campeador. Sancho was killed in the siege of Zamora by the traitor Bellido Dolfos (also known as Vellido Adolfo) in 1072. His brother Alfonso VI took over Leon, Castile and Galicia.