Columbia subject headings:
Architecture and state--Italy--Po River Delta--History--16th century.
Harvard subject headings:
Architecture and state--Italy--Po River Delta--History--16th century.
Castles--Italy--Ferrara Region.
City planning--Italy--Ferrara Region.
Este family--Art patronage.
Ferrara (Italy)--Relations--Italy--Venice.
Venice (Italy)--Relations--Italy--Ferrara.
Princeton subject headings:
Architecture--Italy--Ferrara Region.
Castles--Italy--Ferrara Region.