King Abgar the Great of Edessa (? - A.D. 212) may also play an important role in the history of the Shroud of Turin. Abgar the Great (Abgar VIII) should not to be confused with Abgar V of the legendary account. See: The Legend of Abgar.
Abgar the great is primarily remembered in history for his conversion to Christianity in approximately A.D. 212. However, historian Jack Markwardt thinks that Abgar VIII is the real person of the Legend of Abgar rather than Abgar V. See: An explanation for how the Legend of Abgar evolved.
. . . Avircius Marcellus, the Bishop of Hieropolis, was summoned to Rome, where he was introduced to Abgar’s wife, Queen Shalmath, that he then travelled to Antioch, where he was joined by Palut and provided with the Shroud, identifiable as the historically-documented sacred Christ-icon which had been taken from Palestine to Syria, and that he then proceeded to Edessa, where he displayed the imaged relic to the king and baptized him into the Christian faith, thereby resulting in the Shroud’s commemoration, in legend, as the Portrait of Edessa.
This agrees with a scholarly consensus that Edessa was evangelized and developed as a Christian community at about this time. Scholars doubt that Edessa was converted earlier. It gives us a plausible scenario for seeing how the legend of Abgar might have developed.
Markwardt tells us that the shroud was then returned to Antioch where it remained until the 6th century. It was, he believes, concealed in a niche above the city’s Gate of the Cherubim in 362 where it remained until about 540. The Gate of the Cherubim was so named because, reportedly, according to the biographer of St. Saint Symeon Stylites, the column sitter, Titus placed the Cherubim he took from the Temple in Jerusalem above this gate.
See: Abgar V