Although the Romans had acquired the practice of crucifixion from others they had conquered, it is fair to say that they refined its use and employed it in a particularly gruesome and systematic way. Prior to any discussion of methods employed in these executions, it is well to contemplate the purpose of those methods.
As a form of capital punishment, crucifixion was of course, intended to end in the death of its victim. This was made abundantly clear by the fact that the presiding centurion would forfeit his own life should the condemned man actually survive. However, death of the condemned would provide a relief to both the victim and onlookers by bringing an end to unimaginable suffering.
Although the process was designed to maximize physical pain, it was, as importantly, meant to wholly humiliate its victim and to make clear his complete powerlessness.
Equally important to the Romans was the psychological impact of crucifixion upon the observing public. These open displays of slow, agonizing death made clear to all what penalties they themselves would suffer were they to rebel against the state and its rules. It was so appalling in its effect upon the populace, that it commonly produced in them a tendency to mock and revile the victim rather than any desire to express sympathy. By hurling insults at the condemned, many hoped to prove their loyalty to their overlords.
Also, and quite importantly for the Jews, it was believed that anyone who was hanged on a tree was cursed by God and deserving of the people's revulsion, (Deut. 21:22-23).
Slaves (male and female), criminals, and foreigners were frequently put to death on a cross. It was so frequent that the phrase "in (malam) crucem ire," which translated is "go to an evil cross," became a slang expression equivalent to telling someone to "go to hell." One gets a sense of the inevitability slaves must have felt about crucifixion from one’s declaration in a play by the Roman play write, Plautus (ca. 254–184 BC): "I know that the cross will be my tomb; there my ancestors have been laid to rest, my father, grandfather, great-grandfather, great-great-grandfather."