Columbia subject headings:
Harvard subject headings:
Architects--Spain--Extremadura--16th century.
Architecture--Spain--Extremadura--16th century.
Orden de Alcántara.
Princeton subject headings:
Extremadura (Spain)--Buildings, structures, etc.
Fortification--Spain--Estremadura--History--16th century--Sources.
Military architecture--Spain--Estremadura--History--16th century--Sources.
Orden de Alcántara--History--16th century.