Columbia subject headings:
Italy--History, Military--1268-1559.
Perugia (Italy)--History.
Perugia (Italy)--Relations--Italy--Siena.
Siena (Italy)--History--1355-1557.
Siena (Italy)--Relations--Italy--Perugia.
Harvard subject headings:
Italy--History, Military--1268-1559.
Perugia (Italy)--History.
Perugia (Italy)--Relations--Italy--Siena.
Siena (Italy)--History--1355-1557.
Siena (Italy)--Relations--Italy--Perugia.
Princeton subject headings:
Siena (Italy)--History--1355-1557.