Columbia subject headings:
Castles--Spain--San Fernando.
Fortification--Spain--San Fernando.
San Fernando (Spain)--Buildings, structures, etc.
San Fernando (Spain)--History.
Harvard subject headings:
Castillo de San Romualdo (San Fernando, Spain)
Castles--Spain--San Fernando.
Fortification--Spain--San Fernando.
San Fernando (Spain)--Buildings, structures, etc.
San Fernando (Spain)--History.
Princeton subject headings:
Castillo de San Romualdo (San Fernando, Spain)
Castles--Spain--San Fernando.
Fortification--Spain--San Fernando.
San Fernando (Spain)--Buildings, structures, etc.
San Fernando (Spain)--History.