Before the Second Punic War the army of Rome was a levy of free farmers, who, according to their quality, rode or marched afoot to battle. This was a very good force for wars close at hand, but not the sort of army that will go abroad and bear long campaigns with patience. And moreover as the slaves multiplied and the estates grew, the supply of free- spirited fighting farmers declined. It was a popular leader named Marius who introduced a new factor. North Africa after the overthrow of the Carthaginian civilization had become a semi-barbaric kingdom, the kingdom of Numidia. The Roman power fell into conflict with Jugurtha, king of this state, and experienced enormous difficulties in subduing him. Marius was made consul, in a phase of public indignation, to end this discreditable war. This he did by raising _paid troops_ and drilling them hard. Jugurtha was brought in chains to Rome (106 B.C.) and Marius, when his time of office had expired, held on to his consulship illegally with his newly created legions. There was no power in Rome to restrain him. With Marius began the third phase in the development of the Roman power, the Republic of the Military Commanders. For now began a period in which the leaders of the paid legions fought for the mastery of the Roman world. Against Marius was pitted the aristocratic Sulla who had served under him in Africa. Each in turn made a great massacre of his political opponents. Men were proscribed and executed by the thousand, and their estates were sold. After the bloody rivalry of these two and the horror of the revolt of Spartacus, came a phase in which Lucullus and Pompey the Great and Crassus and Julius Cæsar were the masters of armies and dominated affairs. It was Crassus who defeated Spartacus. Lucullus conquered Asia Minor and penetrated to Armenia, and retired with great wealth into private life. Crassus thrusting further invaded Persia and was defeated and slain by the Parthians. After a long rivalry Pompey was defeated by Julius Cæsar (48 B.C.) and murdered in Egypt, leaving Julius Cæsar sole master of the Roman world.