From a 1989 article by CA Barton on gladiatorial games in Rome: When a gladiator entered the arena, “he took a frightful oath, the sacramentum gladiatorim ; he swore to endure being burned, bound, beaten, and slain by the sword . . . . He foreswore all that might ameliorate his condition, and finally foreswore life itself. By this awful and compulsory vow the condemned emphasized and legitimated his extraordinary position; it becam contractual . . . . Because of the sacramentum , the assumption of a solemn obligation, the gladiator’s fate became a point of honor. Henceforward not to show himself wiling to be burned, bound, beaten, and die would be dishonorable . . . . The gladiator, by his oath, transforms what had originally been an involuntary act to a voluntary one, and so at the very moment that he became a slave condemned to death he becomes a free agent and a man with honor to uphold.”

We can see here one source of the link between baptism and martyrdom, and can begin to imagine what early Latin Christians might have thought when informed that baptism was a sacramentum .