Gaius Cassius Longinus, Consul Suffectus of Rome

http://www.bibleprobe.com/holy_lance.htm

Roman crucifixion was only used since probably about a century before Christ. Crucifixion was considered such a humiliating form of punishment that if you were a Roman citizen, you couldn't be crucified, no matter what the offense. It was usually the execution of choice... for slaves and people considered beneath the dignity of Roman citizenship.

It was a very slow and agonizing form of death. Victims of crucifixion could languish in agony on the cross for up to several days. The dying process could be shortened by breaking the victim's legs so that the victim could no longer push up with their feet for gasps of air. The thieves on both sides of Jesus had their legs broken, but when the Roman soldiers reached Jesus, one of them, reportedly a centurion named Gaius Cassius Longinus (see note below), saw he was already dead and proved it to his fellows by using his spear to pierce the Christ's side. Blood and water poured out. There was no need to break his bones. One must remember, that prior to the cross Jesus has already been tortured via a brutal, all night scourging by Roman soldiers and probably was weak before being nailed to the cross.

The spear itself became a religious relic. The piercing was seen as proof of his death and his subsequent resurrection. It is said that the Spear of Longinus was unearthed by Helena at the same time and place as the Holy Nails and the True Cross. It was later buried at Antioch to prevent its capture by the Saracens.

Of the weapon thus sanctified nothing is known until the pilgrim St. Antoninus of Piancenza (A.D. 570), describing the holy places of Jerusalem, tells us that he saw in the basilica of Mount Sion "the crown of thorns with which Our Lord was crowned and the lance with which He was struck in the side". The mention of the lance at the church of the Holy Sepulcher in the so-called "Breviarus", as M. de Mely points out (Exuviae, III, 32), is not to be relied on. On the other hand, in a miniature of the famous Syriac manuscript of the Laurentian Library at Florence, illuminated by one Rabulas in the year 586, the incident of the opening of Christ's side is given a prominence which is highly significant. Moreover, the name Longinus -- if, indeed, this is not a later addition -- is written in Greek characters (LOGINOS) above the head of the soldier who is thrusting his lance into our Savior's side. This seems to show that the legend which assigns this name to the soldier Longinus (see Note below), who, according to the same tradition, was healed of ophthalmia and converted by a drop of the precious blood spurting from the wound) is as old as the sixth century. And further it is tempting, even if rash, to conjecture that the name Logginos, or Logchinos is in some way connected with the lance (logche). Be this as it may, a spear believed to be identical with that which pierced our Savior's body was venerated at Jerusalem at the close of the sixth century, and the presence there of this important relic is attested half a century earlier by Cassiodorus (In Ps. lxxxvi, P.L., LXX, 621) and after him by Gregory of Tours (P.L., LXXI, 712). In 615 Jerusalem was captured by a lieutenant of the Persian King Chosroes. The sacred relics of the Passion fell into the hands of the pagans, and, according to the "Chronicon Paschale", the point of the lance, which had been broken off, was given in the same year to Nicetas, who took it to Constantinople and deposited it in the church of St. Sophia. This point of the lance, which was now set in an "yeona", or icon, many centuries afterwards (i.e., in 1244) was presented by Baldwin to St. Louis, and it was enshrined with the Crown of Thorns (q.v.) in the Sainte Chapelle. During the French Revolution these relics were removed to the Bibliotheque Nationale, and, although the Crown has been happily preserved to us, the other has now disappeared.

http://www.catholic-saints.info/patron-saints/saint-longinus.htm