Columbia subject headings:
Alfonso VI, King of Castile and Leon, 1030-1109.
Castile (Spain)--History--Alfonso VI, 1065-1109.
Harvard subject headings:
Alfonso VI, King of Castile and Leon, 1030-1109
Castile (Spain)--History--Alfonso VI, 1065-1109--Sources.
Diplomatics--Spain.
Leon (Kingdom)--History--Sources.
Princeton subject headings:
Alfonso VI, King of Castile and Leon, 1030-1109.
Castile (Spain)--History--Alfonso VI, 1065-1109.