For the hunts the arena was transformed into a forest where wild beasts were released and men armed with spears came into combat with them. Variety was sought in this spectacle by employing the rarest animals--lions, panthers, elephants, bears, buffaloes, rhinoceroses, giraffes, tigers, and crocodiles. In the games presented by Pompey had already appeared seventeen elephants and five hundred lions; some of the emperors maintained a large menagerie. Sometimes instead of placing armed men before the beasts, it was found more dramatic to let loose the animals on men who were naked and bound. The custom spread into all cities of the empire of compelling those condemned to death to furnish this form of entertainment for the people. Thousands of persons of both sexes and of every age, and among them Christian martyrs, were thus devoured by beasts under the eyes of the multitude. =The Gladiators.=--But the national spectacle of the Romans was the fight of gladiators (men armed with swords). Armed men descended into the arena and fought a duel to the death. From the time of Cæsar[152] as many as 320 pairs of gladiators were fought at once; Augustus in his whole life fought 10,000 of them, Trajan the same number in four months. The vanquished was slain on the field unless the people wished to show him grace. Sometimes the condemned were compelled to fight, but more often slaves and prisoners of war. Each victory thus brought to the amphitheatre bands of barbarians who exterminated one another for the delight of the spectators.[153] Gladiators were furnished by all countries--Gauls, Germans, Thracians, and sometimes negroes. These peoples fought with various weapons, usually with their national arms. The Romans loved to behold these battles in miniature. There were also, among these contestants in the circus, some who fought from their own choice, free men who from a taste for danger submitted to the terrible discipline of the gladiator, and swore to their chief "to allow themselves to be beaten with rods, be burned with hot iron, and even be killed." Many senators enrolled themselves in these bands of slaves and adventurers, and even an emperor, Commodus, descended into the arena.