Roman salute
Noun: a manner of military salutation allegedly peculiar to ancient Rome, in which the right arm and hand are extended and elevated in the direction of any superior officer, or in the absence of any such superior, in the geographical direction of Rome itself, accompanied by the Latin phrase "Ave Caesar" ("Hail Caesar").
"Immediately upon taking command of the Antonia fortress, the tribune Messala executed the Roman salute to the former fortress commandant."