The meaning of the cross will vary, depending on the type of cross used. For example, when speaking of the biblical cross such as those found in the Old Testament, the cross used by the ancient Jews was modeled after the Greek Tau which is represented in an uppercase English T. An example of this early cross is depicted in this 15th or early 16th century painting below, of Jesus on the Tau from the School of Brugge.
However, when Rome had introduced Christianity in the time of Constantine under the banner of war, the cross was changed to the Greek theta which is the symbol of death, that the Roman Emperors and Catholic Bishops had used as their standard for Christian warfare. Simply put, salvation is not for everyone.
After all, this was and has been an age of intense warfare all across the world, and in order to combat their enemies, the Church would ensure that they would officially symbolize this time with the appropriate ensigns. These facts are confirmed by one of the most important Church Fathers, St. Augustine who had primarily rejected self-defense, but he also advocated it with one exception: when a soldier acts in self-defense and in defense of others. He had considered it a sin, for a peaceful people not to defend themselves such as the Christians when faced with grave wrong. Augustine had said, "Defense of one's self or others could be a necessity, especially when authorized by a legitimate authority." He also tells us that the image of Christ and his Cross was the new ensign of Christian Warfare that the Romans had carried before them; being the Ensign or Profession of their Warfare. Hence, the authorized use of warfare under the banner of Christianity and the ensign of the cross was almost always sanctioned by the Church Fathers since the inception of the church.
The first documented use of the Greek theta as the cross and as a symbol of Christian warfare was mainly introduced to the church under the Christian warlord Constantine in the 4th century. It came into use after the Emperor Constantine had dreamed a vision of St. Nicholas, who told him that three men were about to die on charges of necromancy, but they were innocent, and if they were not released, war would desolate the island. Constantine set them free. He also had a dream of Christ who had appeared with a cross in his hand and ordered the ruler to have a standard made like it. Constantine had the cross impressed on the arms of his soldiers and erected large crosses in Constantinople and on the Hippodrome.
Later in the year 629 A.D., after warring with the Persians, Emperor Heraclius enters Constantinople with the cross in triumph after his military victory over the Persian Empire. More history confirms this use of the cross as the ensign of Christian Warfare: Saint Bede had written about the Saxon King Oswald (635 A.D.), who, being in imminent danger in war, erected and offered adoration to a cross, by which victory was secured. (Hist EccL Hi. 2).
33rd degree Scottish Rite, Albert Pike had written in Morals and Dogma, about a ninth century king of the Picts in Scotland, Hungus who before going into battle, had a vision of the cross just like Constantine had 500 years earlier;
A MIRACULOUS tradition, something like that connected with the labarum of Constantine, hallows the Ancient Cross of St. Andrew. Hungus, who in the ninth century reigned over the Picts in Scotland, is said to have seen in a vision, on the night before a battle, the Apostle Saint Andrew, who promised him the victory; and for an assured token thereof, he told him that there should appear over the Pictish host, in the air, such a fashioned cross as he had suffered upon. Hungus, awakened, looking up at the sky, saw the promised cross, as did all of both armies; and Hungus and the Picts, after rendering thanks to the Apostle for their victory, and making their offerings with humble devotion, vowed that from thenceforth, as well they as their posterity, in time of war, would wear a cross of St. Andrew for their badge and cognizance.
THE TRUE CROSS
The letter Tau, Bede has written as the sign of salvation and of the cross. The Tau is represented by an uppercase Τ and is the 19th letter of the Greek alphabet. The Greek alphabet is derived from the Phoenicians who had represented it with the Phoenician letter taw . The tau is considered a symbol of salvation due to the identification of the tau with the sign which in Ezechiel 9:4 was marked on the forehead of the saved ones (וְהִתְוִיתָ תָּו עַל־מִצְחֹות הָאֲנָשִׁים "set a mark (tav; after the Phoenician cross-shape on the forehead of the men"), or due to the tau-shaped outstretched hands of Moses in Exodus 17:11
The cross of the Tau can be found as St. Anthony's Cross, Old Testament Cross, Anticipatory Cross, Cross Commissee, Egyptian Cross, Advent Cross, Croce taumata, Saint Francis's Cross,and Crux Commissa. It is usually considered as the symbol of Franciscan orders, due to St. Francis' love for it, the symbol of the redemption and of the Cross. Fellow Franciscan, Augustine of Hippo is honored all over the world as the Patron Saint for lost articles, and even lost spiritual goods and for his good works. Almost all Franciscan churches have painted a tau with two crossing arms, both with stigmata, the one of Jesus and the other of Francis; usually members of the Secular Franciscan Order wear a wooden τ in a string with three knots around the ankle. (Wikipedia)
THE CROSS OF CHRISTIAN WARFARE
The cross is the lower case t; Greek for [theta which is simply not the same as the letter Tau because it has a completely different meaning and numerical value. Theta is the eighth letter of the Greek alphabet and would represent the value of 9 which is the Son of Man hanging on the cross and is considered the symbol of death. Nine (9) is sacred because it is the "first cube of an odd number (3)" and why Jesus had died at age 33 in the year 33 A.D. He was crucified at Golgatha, the Place of the Skull.
A temple was built there, but later was destroyed and a temple to Venus built upon it.
This is confirmed by Eusebius, who had written the emperor Constantine;
“not without divine admonition,” resolved to uncover the holy tomb. He states that wicked men had covered it over with earth and rubbish, and had erected on the spot a temple of Venus. These were removed, and the tomb and Golgotha laid bare. A magnificent church was built over them, and consecrated in A.D. 335 ( Vil. Constantiii. iii, 2G-33). There can be little doubt that the present Church of the Sepulchre occupies the site of that built by Constantine.
In classical Athens, it was used as an abbreviation for the Greek θάνατος (thanatos, “death”), as it vaguely resembles a human skull. [theta was used as a warning symbol of death, in the same way that skull and crossbones are used in modern times. The most powerful secret college fraternity at Yale University, Skull and Bones uses this symbol and has also pumped out presidents such as George Bush Jr. and many other powerful men who have went on to hold positions of power. It is no secret, that when you hold such power, you often hold life and death decisions in your hands, and in a time of war, these life or death decisions such as going to war or military campaigns are part of what goes along with such power. The same decisions that were made by Alexander the Great, Augustus Caesar, and Constantine.
When Bede tells us that letter Tau is written as the sign of salvation and of the cross, he is not talking about the Theta which is the lower case 't', but the Tau which is an uppercase 'T'. With the symbol of Jesus, St Mark informs us, “With the form of a serpent, He kills the serpent, for the serpent made out of the rod swallowed up the other serpents.” Jesus was crucified on the Christian Cross of Warfare on Friday, April 3, AD 33.
This is why the church believes salvation is not for everyone.