The death penalty by Crucifixion only kills slowly. Crucifixion kills by means of a slow suffocation. The loss of blood from hands and feet is soon stopped and rarely proves fatal. Even the same nails may help to stop the blleding.The real cause of death is the forced tension of the limbs that produces rigidity of the whole body and increasing difficulties in breathing. The blood circulation is slowed down also. The condemned is then forced to push up on his pierced feet and pull up with his arms sufficiently to raise and lower his body in order to breath. The Romans used to hasten the deaths of the crucified by breaking their legs below the knees with blows applied with mallets or iron clubs. This method is known as crurifragium. The cruelty of this is hard to imagine. Crurifragium kept the victim from pushing his body upward from the suffocation position so that death came in a few minutes. It might be said that it was very cruel method, but certainly was also necessary and merciful for the victim. The Two Thieves, but on seeing that Jesus was already dead, left his legs unbroken. Gestas screamed in agony as his legs were shattered with dreadful blows, while Dismas endured the punishment as a final liberation. Death of both followed quickly.