Popular factions supported favourite gladiators and gladiator types. Early literary sources seldom agree on the origins of gladiators and the gladiator games. Some groups were banned altogether from the Colosseum, notably gravediggers, actors and former gladiators. It may have resembled the later manica armour used by Roman gladiators and cataphract cavalry. Many skeletons have been found buried with only a single greave, including gladiators and soldiers. The amphitheatre was part of the circuit of the gladiators. He is also the owner of the Rome Gladiators. Ali hosted the revival of "American Gladiators" alongside Hulk Hogan. Slaves were used for labour, as well as for amusement (e.g. gladiators and sex slaves). Caligula began auctioning the lives of the gladiators at shows. These new gangs were trained and led by experienced gladiators. The Atlanta Gladiators of the ECHL Play in Duluth, a suburb northeast of the city. In international Gladiators 2 and both Ashes competitions, he competed for Australia. Bollea hosted the comeback series of "American Gladiators" on NBC in 2008. USA Network was the first network to air reruns of "American Gladiators".