Columbia subject headings:
Harvard subject headings:
Praetorian Guard--History.
Rome--Army--History.
Rome--History, Military--30 B.C.-476 A.D.
Rome--History--Empire, 30 B.C.-284 A.D.
Special forces (Military science)--Rome--History.
Princeton subject headings:
Praetorian Guard--History.
Rome--Army--History.
Special forces (Military science)--Rome--History.