Not much is known for a fact about St. Bartholomew. He was born at Cana, is always mentioned in the gospels with St. Philip, and was present at the Ascension. He is mentioned by name in the synoptic gospels (Matthew, Mark and Luke) and tradition holds that John refers to him as Nathanael. Beyond this, the rest of what we believe about Bartholomew comes from tradition.
It is said that Bartholomew went on a mission to modern day Bombay and left behind a copy of Matthew's gospel. Along with St. Jude, Bartholomew brought Christianity to Armenia. According to tradition, he converted the Armenian king Polymius. This did not sit well with Polymius' brother Astyages who had Bartholomew executed in Albanopolis. There are two competing accounts of his martyrdom. The first say that Bartholomew was beheaded. The second and more widely accepted is that he was flayed alive and then crucified upside down. It is for this reason that Bartholomew is often depicted in artwork holding a knife and his own flayed skin.
Bartholomew is also associated with several miracles on the island of Lipari in Italy. The first concerns the traditional procession held on the Feast of St. Bartholomew. Each year, the people would process with he statue to honor the saint. One year, the statue became to heavy to carry and had to be put down so the statue-bearers could rest. Each time they continued the statue became heavy again causing them to rest and lengthening the time of the procession. Meanwhile, as the procession was coming over a hill and looking down on the town the walls of the town collapsed. The townspeople credited St. Bartholomew with their lives as all of them would have been killed in the collapse had the procession not taken longer.
The second miracle occurred during World War II. During the war the Fascist government ordered all silver to be turned in and melted down to finance the war efforts. This included a silver statue of St. Bartholomew. Although the statue weighed several kilograms, when it was handed over the government found that it only weighed several grams. The statue was then returned unharmed as it was deemed an insignificant amount of silver.