Despite being one of the original twelve apostles, very little information is known about Saint Bartholomew. In the Gospels, he is only mentioned with the apostles are listed (Mark 3:18, Matthew 10:3, Luke 6:14, and Acts 1:13). Scholars believe he is referred to in John 1:43-51 when Jesus said
"Behold, an Israelite indeed, in whom is no guile"
When the second century teacher Saint Panaenus of Alexandria made a visit to India, he found a Hebrew copy of the Gospel of Matthew. Both Eusebius of Caesarea and Saint Jerome (both fourth century) refered to the tradition that Saint Bartholomew travelled to India (specifically the Bombay region) for his missionary activities.
Another tradition (which doesn't preclude his trips to India) was that Saint Bartholomew and the apostle Jude (Thaddeus) traveled to Armenia to bring Christianity there in the first century. The Armenian Apostolic Church names both as patron saints. The traddition holds that for trying to convert Polymius the King of Armenia to Christinity was ordered to be executted and tortured by the king's brother. The tradition holds that he was flayed alive and beheaded, while another states that he was crucified upside down (as was Peter). In his book The Twelve: Lives and Legends of The Apostles Frances Spilman quotes a historical find that indicates his death at Kalyan in India.
Two Miracles in Italy are attributed to him. The first in the town of Lipari - where the towns people acrried a statues from inside the cathedral each year on his feast day and carry it around the town. On one morning, the statue became heavy, and each time men tried to carry it, the statue became heavier until it was too heavy to carry. The walls down hill suddenly collapsed, and had the statue not been too heavy to carry the carriers would have been killed.
The other happened during WW2. When the facist government of Italy attempted to raise funds through melting the statue, they first had it weighed. Officially when weighed by the regime, the statue weighed only a few grams. In reality the statue is several kilograms of silver, and the miracle prevented the statue's destruction.
He is the patron saint of (among many others) Armenia, bookbinders, butchers, neurological diseases, skin diseases and leather workers.