A similar view was put forward by John Denham Parsons in 1896.
The stauros used as an instrument of execution was (1) a small pointed pole or stake used for thrusting through the body, so as to pin the latter to the earth, or otherwise render death inevitable; (2) a similar pole or stake fixed in the ground point upwards, upon which the condemned one was forced down till incapable of escaping; (3) a much longer and stouter pole or stake fixed point upwards, upon which the victim, with his hands tied behind him, was lodged in such a way that the point should enter his breast and the weight of the body cause every movement to hasten the end; and (4) a stout unpointed pole or stake set upright in the earth, from which the victim was suspended by a rope round his wrists, which were first tied behind him so that the position might become an agonising one; or to which the doomed one was bound, or, as in the case of Jesus, nailed. That this last named kind of stauros, which was admittedly that to which Jesus was affixed, had in every case a cross-bar attached, is untrue; that it had in most cases, is unlikely; that it had in the case of Jesus, is unproven.
Even as late as the Middle Ages, the word stauros seems to have primarily signified a straight piece of wood without a cross-bar. For the famous Greek lexicographer, Suidas, expressly states, "Stauroi; ortha xula perpegota," and both Eustathius and Hesychius affirm that it meant a straight stake or pole.
The side light thrown upon the question by Lucian is also worth noting. This writer, referring to Jesus, alludes to "That sophist of theirs who was fastened to a skolops"; which word signified a single piece of wood, and not two pieces joined together.
— John Denham Parsons, The Non-Christian Cross, 1896
In the 20th century, William Edwy Vine also reasoned that the stauros as an item for execution was different to the Christian cross. Vine's Expository Dictionary's definition states that stauros:
denotes, primarily, "an upright pale or stake." On such malefactors were nailed for execution. Both the noun and the verb stauroo, "to fasten to a stake or pale," are originally to be distinguished from the ecclesiastical form of a two beamed "cross." The shape of the latter had its origin in ancient Chaldea, and was used as the symbol of the god Tammuz (being in the shape of the mystic Tau, the initial of his name) in that country and in adjacent lands, including Egypt. By the middle of the 3rd cent. A.D. the churches had either departed from, or had travestied, certain doctrines of the Christian faith. In order to increase the prestige of the apostate ecclesiastical system pagans were received into the churches apart from regeneration by faith, and were permitted largely to retain their pagan signs and symbols. Hence the Tau or T, in its most frequent form, with the cross-piece lowered, was adopted to stand for the "cross" of Christ.
— William Edwy Vine, An Expository Dictionary of New Testament Words, 1940