The following is a collection of thoughts on this subject from Rud P., Jan H. and myself.
Jehovah's Witnesses tell us that Jesus died on a "torture stake" and not on a cross. They point out that the Greek word used in the New Testament which is commonly translated as "cross" primarily means an upright stake or pole. However, it is also known from several reliable historical sources that the Romans did in fact often attach a cross piece to a stake or pole when using that stake or pole as an instrument of torture and execution. So, how can we know if the Romans attached a cross piece to the stake or pole which Jesus was nailed to? I believe there are several indications in the Bible that Christ did, in fact, die on a "cross."
First of all, John 20:25 indicates that "nails" (plural) were driven through Jesus' hands at the time of his execution. Two nails, one through each hand, would have been required to nail Jesus to a cross, but only one nail would have been needed to hold both of Jesus' hands to a torture stake, if his arms were raised over his head with his hands together. For this reason, pictures in the Society's publications of Jesus on a torture stake always show only one nail through both of Christ's hands. So, John 20:25 seems to point to a cross as the instrument used to put Jesus to death.
Also to be considered is the fact that the Bible tells us a sign was placed "over his head" at the time of Christ's death. (Mt. 27:37) However, the Society's pictures of Christ on a torture stake always show this sign placed over Christ's hands, not directly over his head. Why? Because if Christ's arms were raised over his head and his hands were then nailed to a torture stake there would have been no room to attach such a sign "over his head." Now, I suppose it may be said that any sign that was attached to a torture stake over Jesus' hands would have also been "over his head." But if that sign was actually attached over Christ's hands, as the Society's pictures of Jesus on a torture stake illustrate, why did Matthew say that sign was placed "over his head" rather than "over his hands?"
Then there are the Old Testament symbolisms which many believe point to the fact that Christ would die on a cross. One is the blood that was splashed "upon the two doorposts and the upper part of the doorway" during the Jews' Passover celebration. (Ex.12:7) This cross of blood is believed by many Christians to have pointed to the fact that Jesus Christ would later shed his blood on a cross at Passover time for the forgiveness of our sins.
Many also believe that another historical account in the Old Testament was meant to prefigure the fact that Christ would die on a cross. That account is found in Exodus 17:11,12. There we read how the Israelites were only victorious in battle when Moses' hands were held up for him, "one on one side and one on the other." It is said that this account was meant by God to point to the time when mankind would gain victory over sin and death, a victory which would only be gained when Jesus' hands were held up for him on the cross, "one on one side and one on the other."
The WTS is quite alone in asserting this view that Jesus was killed on a simple stake. No religious denomination that I know of supports the WTS here, except some very few "Name"-groups in the United States. More importantly, no historian in the world (secular or religious) currently agrees with the WTS that there is any evidence whatsoever that Jesus died on a stake without a crossbeam. Neither have the WTS ever presented the slightest bit of real evidence for its claims.
A fact quite ignored by the WTS, is that there is definite extrabiblical evidence to the exact shape of the "stauros," and this shape is the cross, a T with a lowered crossbeam.
First, there are quite a few descriptions in early Christian texts. Note that these were written while the Biblical Greek language was still alive, and while the cruel execution practice we call crucifixion was still carried out by the Romans.
The Christian apologist Justin, writing about 160 CE (long before Constantin) made mention of the shape of the cross at least twice:
"And the human form differs from that of the irrational animals in nothing else than in its being erect and having its hands extended . .. and this shows no other form than that of the cross." (Justin Martyr: "First Apology" in Roberts & Donaldson (ed): Ante-Nicene Fathers, Vol I, Eerdmans 1969, p. 181)
"For the one beam is placed upright, from which the highest extremity is raised up into a horn, when the other beam is fitted on to it, and the ends appear on both sides as horns joined on to the one horn." (Justin's "Dialogue With Trypho", Chap XC in ANF, p. 245)
A few decades later Irenaeus wrote:
"The very form of the cross, too, has five extremities, two in length, two in bredth, and one in the middle, on which [last] the person rests who is fixed by the nails." (Irenaeus' "Against Heresies", Chap XXIV in ANF p. 395)
In 197 AD the Christian writer Tertullian wrote:
"Every piece of timber which is fixed in the ground in an erect position is a part of a cross, and indeed the greater portion of its mass. But an entire cross is attributed to us, with its transverse beam, of course, and its projecting seat." (Tertullian in "Ad Nationes" Chap XI in ANF, Vol III, p. 122)
Note that these writers lived in a period when Crucifixions were still carried out, and could see these horribly executions firsthand. Both Justin and Tertullian referred to cases where Christians were crucified (See ANF, Vol I, p. 254; Vol III, p. 28).
We even find testimony about the form of the cross by early non-Christian writers. The Greek writer Lukianos (c. 120-180 AD) wrote that the letter T had received its "evil meaning" because of the "evil instrument tyrants put up to hang people upon them. (Lukianos in "Iudicium Vocalium 12", in Martin Hengel in Crucifixion, Fortress Press, 1982, pp. 8,9)
Together, this overwhelming evidence speaks for itself. Why the Watchtower Society has gone to such great lengths to create a completely imaginary case for a "stauros" with no crossbeam is puzzling, but it no doubt have something to do with a need to distinguish itself from other denominations. It should also demonstrate for all how little regard the WTS have for truth. All this information has been made available to the WTS many times.
Medical Evidence for Crucifixion
It is a fact that the way Jesus' execution is depicted in Watchtower publications would have killed him in about six minutes.
Already in 1948 did the Austrian doctor Hermann Moedder demonstrate that if you hang a person with his hands right up, he will die from suffocation within about six minutes. This has been confirmed a number of times, lately by a professor in pathology with the University of Columbia, who also demonstrated experimentally that if the person is nailed with his arms outright in an angle of 60-70 degrees, he can live for several hours. His work also showed that it is possible to nail a person to a cross through the hands, not necessarily the wrist as earlier indicated. (Frederick T. Zugibe: "Two Questions About Crucifixion" in Bible Review , April 1989)
So this evidence shows definitely that it isn't even anatomically possible for Jesus to have been crucified as shown in Watchtower publications.
Is the Cross a Pagan Symbol?
Sure. And among these ancient pagan nations who had crosses were the Romans, who selected the torture device that was used to kill Jesus.
It's very strange that the WTS has this obsession with the cross being a "pagan phallic symbol", and then argues that a pole which is described many times as a pagan fertility symbol in the very Bible, was used to kill Jesus.