The Senate did not initially take the slave rebellion seriously, until they believed Rome itself was under threat. Crassus offered to equip, train, and lead new troops, at his own expense, after several legions had been defeated and their commanders killed in battle or taken prisoner. Eventually, Crassus was sent into battle against Spartacus by the Senate. At first he had trouble both in anticipating Spartacus' moves and in inspiring his army and strengthening their morale. When a segment of his army fled from battle, abandoning their weapons, Crassus revived the ancient practice of decimation – i.e., executing one out of every ten men, with the victims selected by drawing lots. Plutarch reports that "many things horrible and dreadful to see" occurred during the infliction of punishment, which was witnessed by the rest of Crassus' army. Nevertheless, according to Appian, the troops' fighting spirit improved dramatically thereafter, since Crassus had demonstrated that "he was more dangerous to them than the enemy."