Cæsar promptly took his resolve: he would appeal to the arbitrament of
arms. He had the enthusiastic devotion of his soldiers, the great mass
of whom, being provincials or foreigners, cared very little for the
country whose name they bore. Accordingly, in January, 49 B. C., he
advanced from his headquarters at Ravenna to the little stream, the
Rubicon, which separated his own province and command from Italy. The
crossing of this river was in reality a declaration of war against the
republic; and it is related that, upon arriving at the Rubicon, Cæsar
long hesitated whether he should take this irrevocable step. After
pondering many hours he at length exclaimed, “The die is cast!” and
plunged into the river.
Pompey concluded not to attempt to defend Italy, but to retire upon the
East, where he would gather a great army and then return to overwhelm
the “usurper.” Accordingly he retreated to Greece.