Bartholomew was one of the Twelve Apostles of Jesus, and is usually identified with Nathanael (alternatively spelled Nathaniel), who appears in the Gospel according to John as being introduced to Christ by Philip, who would also become an Apostle, John 1:43-51 He is also identified as "Nathanael of Cana in Galilee" in John 21:2.
Eusebius of Caesarea's Ecclesiastical History (5:10) states that after the Ascension, Bartholomew went on a missionary tour to India, where he left behind a copy of the Gospel of Matthew. Other traditions record him as serving as a missionary in Ethiopia, Mesopotamia, Parthia, and Lycaonia.
Along with his fellow apostle Jude Thaddeus, Bartholomew is reputed to have brought Christianity to Armenia in the 1st century. Thus, both saints are considered the patron saints of the Armenian Apostolic Church.
He is said to have been martyred in Albanopolis in Armenia. According to one account, he was beheaded, but a more popular tradition holds that he was flayed alive and crucified, head downward. He is said to have converted Polymius, the king of Armenia, to Christianity. Astyages, Polymius' brother, consequently ordered Bartholomew's execution which tradition says was by being flayed alive to take off his skin.
The 13th century Saint Bartholomew Monastery was a prominent Armenian monastery constructed at the site of the martyrdom of Apostle Bartholomew in the Vaspurakan Province of Greater Armenia (now in southeastern Turkey).
According to the Synaxarium of the Coptic Orthodox Church, his martyrdom is commemorated on the 1st day of the Coptic Calendar (1st day of the month of "Thout"), which currently falls on September 11 (corresponding to August 29 in the Gregorian Calendar). His feast is June 11 in Eastern Christianity, and August 24 in both forms of the Roman Rite of the Catholic Church.
St Bartholomew by Albrecht Dürer
He is shown with the knife used to flay him and the Gospel of St Matthew he took to India