In St. John's Gospel, Bartholomew is known by the name Nathaniel (the liturgy does not always seem aware of this identity). He hailed from Cana in Galilee, was one of the first disciples called by the Lord. On that initial meeting Jesus uttered the glorious compliment: "Behold, an Israelite indeed in whom there is no guile!" After the Resurrection he was favored by becoming one of the few apostles who witnessed the appearance of the risen Savior on the sea of Galilee (John 21:2). Following the Ascension he is said to have preached in Greater Armenia and to have been martyred there. While still alive, his skin was torn from his body. The Armenians honor him as the apostle of their nation. Concerning the fate of his relics, the Martyrology says: "His holy body was first taken to the island of Lipari (north of Sicily), then to Benevento, and finally to Rome on an island in the Tiber where it is honored by the faithful with pious devotion."

The Church of Armenia has a national tradition that St. Jude Thaddeus and St. Bartholomew visited the Armenians early in the first century and introduced Christianity among the worshippers of the god Ahura Mazda. The new faith spread throughout the land, and in 302 A.D., St. Gregory the Illuminator baptized the king of Armenia, Dertad the Great, along with many of his followers. Since Dertad was probably the first ruler to embrace Christianity for his nation, the Armenians proudly claim they were the first Christian State.

http://www.catholicculture.org/culture/liturgicalyear/calendar/day.cfm?date=2013-08-24