Having killed a boy of his own age at only thirteen, he was banished from Florence; and in Rome he then associated with prostitutes and other undesirables. His cousin Pope Leo X employed him in the papal army, where he earned himself a reputation of violence but also of military excellence. After a while he founded his own group of soldiers of fortune. With a simple tunic and strict discipline, he led them into rape and pillaging wherever the opportunity arose. He also 
moernised guerilla warfare by using light horses and attacking by surprise. He spent his short life in battle, hunting and womanizing, and died almost an outcast of a gangrenous wound.

Source: Leo van de Pas