Crucifixion was often performed to terrorize and dissuade the onlookers from perpetrating the crimes punishable by it. Victims were left on display after death as warnings so that others who attempt dissent might be forewarned. Crucifixion was usually intended to provide a death that was particularly slow, painful (hence the term excruciating, literally "out of crucifying"), gruesome, humiliating, and public, using whatever means were most expedient for that goal. Crucifixion methods varied considerably with location and time period.

The Greek and Latin words corresponding to "crucifixion" applied to many different forms of painful execution, from impaling on a stake to affixing to a tree, to an upright pole (a crux simplex) or to a combination of an upright (in Latin, stipes) and a crossbeam (in Latin, patibulum).[6]

In some cases, the condemned was forced to carry the crossbeam on his shoulders to the place of execution. A whole cross would weigh well over 300 pounds (135 kilograms), but the crossbeam would weigh only 75–125 pounds (35–60 kilograms).[7] The Roman historian Tacitus records that the city of Rome had a specific place for carrying out executions, situated outside the Esquiline Gate,[8] and had a specific area reserved for the execution of slaves by crucifixion.[9] Upright posts would presumably be fixed permanently in that place, and the crossbeam, with the condemned person perhaps already nailed to it, would then be attached to the post.

The person executed may have been attached to the cross by rope, though nails are mentioned in a passage by the Judean historian Josephus, where he states that at the Siege of Jerusalem (70), "the soldiers out of rage and hatred, nailed those they caught, one after one way, and another after another, to the crosses, by way of jest."[10] Objects used in the crucifixion of criminals, such as nails, were sought as amulets with perceived medicinal qualities.[11]

While a crucifixion was an execution, it was also a humiliation, by making the condemned as vulnerable as possible. Although artists have depicted the figure on a cross with a loin cloth or a covering of the genitals, writings by Seneca the Younger suggest that victims were crucified completely nude.[12] When the victim had to urinate or defecate, they had to do so in the open, in view of passers-by, resulting in discomfort and the attraction of insects. Despite its frequent use by the Romans, the horrors of crucifixion did not escape mention by some of their eminent orators. Cicero for example, in a speech that appears to have been an early bid for its abolition,[13] described crucifixion as "a most cruel and disgusting punishment", and suggested that "the very mention of the cross should be far removed not only from a Roman citizen’s body, but from his mind, his eyes, his ears."[13]

Frequently, the legs of the person executed were broken or shattered with an iron club, an act called crurifragium, which was also frequently applied without crucifixion to slaves.[14] This act hastened the death of the person but was also meant to deter those who observed the crucifixion from committing offenses.[14]