Apostle, who is commonly believed to the same person as Nathaniel, sprung from Cana in Galilee, he was led by Philip to Christ Jesus at the Jordan; later the Lord called him to follow Him and we was reckoned among the Apostles; after the Ascension of the Lord it is traditionally held that he preached the Gospel in India and there was crowned with martyrdom.[At the time "India" was understood as all the lands lying outside of, and east of, the Roman and Parthian Empires. This included not only present-day India proper, but also Abyssinia, the "prosperous Arabia," and Caramenia.]

Here is the Church in Rome where the body of the Apostle is found.  San Bartolomeo is on the island in the Tiber River.
Here is the Roman Martyrology entry for today’s saint, the Apostle Bartholomew:
Festum sancti Bartholomaei, Apostoli, qui idem ac Nathanael plerumque creditus, Canae Galilaeae ortus, apud Iordanem a Philippo ad Christum Iesum ductus est; postea Dominus ad se sequendum eum vocavit et Duodecim aggregavit; post Ascensionem Domini Evangelium in India ipse praedicasse traditur ibique martyrio coronatus esse.

In the Roman Catholic church, saints and martyrs are commemorated on their feast days through the daily reading of the Roman Martyrology. The entry for 24 August, St. Bartholomew's feast day, reads as follows:

The apostle St. Bartholomew, who preached the Gospel of Christ in India.  Passing thence into the Greater Armenia where, after converting many to the faith, he was flayed alive by the barbarians, and having his head cut off by order of King Astyages, he fulfilled his martyrdom.  His holy body was first carried to the island of Lipara, then to Benevento, and finally to Rome in the Island of the Tiber, where it is venerated by the pious faithful.

The medieval version of the origin of this late Apostles' Creed read:

"On the tenth day after the ascension when the disciples were gathered for fear of the Jews, the Lord sent the promised Paraclete. And when he had come as a flaming fire and they were filled with the knowledge of all tongues, they composed this symbol. Peter said: I believe in God the Father almighty, maker of heaven and earth. Andrew said: And in Jesus Christ his only Son, our Lord. James said: Who was conceived by the holy Spirit, born of Mary the virgin. John said: Suffered under Pontius Pilate, was crucified, dead, and buried. Thomas said: Descended into Hades, on the third day rose from the dead. James said: Ascended into heaven, sitteth at the right hand of God the Father almighty. Philip said: Thence he is about to come to judge quick and dead. Bartholomew said: I believe in the holy Spirit. Matthew said: Holy catholic church, communion of saints. Simon said: Remission of sins. Thaddeus said: Resurrection of the flesh. Matthias said: Life eternal." 

The Apostle Bartholomew travelled far from Jerusalem, into the most distant parts of the region of India, carrying the word of Christ's resurrection, the need for baptism and repentance, and the coming of the Kingdom of God. Like many pilgrims and the poor of the area, he took up residence in the temple of a local idol called Astaruth. But his presence immediately began disrupting "normal" life at the temple.

Apparently, Astaruth convinced his followers of his power by first making them physically ill (without their knowledge). When the sick travelled to his temple and offered the appropriate sacrifices, Astaruth removed their afflictions and gained their worship. But when Bartholomew entered the area, Astaruth's apparent ability to cure the sick failed, because the presence of Christ's apostle robbed the demon of his power:

And having there sacrificed, they demanded, asking why their god Astaruth had not responded to them. And the demon Becher answered and said to them: From the day and hour that the true God, who dwelleth in the heavens, sent his apostle Bartholomew into the regions here, your god Astaruth is held fast by chains of fire, and can no longer either speak or breathe. They said to him: And who is this Bartholomew? He answered: He is the friend of the Almighty God, and has just come into these parts, that he may take away all the worship of the idols in the name of his God.
The news of Bartholomew's power spread quickly, as his ability to control Astaruth and Beliar became more apparent. Finally the king of the region, a man named Polymius, brought his daughter to the Apostle for healing.

And Polymius, the king of that country, happened to be standing opposite the apostle; and he had a daughter a demoniac, that is to say, a lunatic. And he heard about the demoniac that had been healed, and sent messengers to the apostle, saying: My daughter is grievously torn; I implore thee, therefore, as thou hast delivered him who suffered for many years, so also to order my daughter to be set free. And the apostle rose up, and went with them. And he sees the king's daughter bound with chains, for she used to tear in pieces all her limbs; and if any one came near her, she used to bite, and no one dared to come near her. The servants say to him: And who is it that dares to touch her? The apostle answered them: Loose her, and let her go. They say to him again: We have her in our power when she is bound with all our force, and dost thou bid us loose her? The apostle says to them: Behold, I keep her enemy bound, and are you even now afraid of her? Go and loose her; and when she has partaken of food, let her rest, and early to-morrow bring her to me. And they went and did as the apostle had commanded them; and thereafter the demon was not able to come near her.
This excerpt from an early hymn, originally published in F. J. Mone's Latin Hymns of the Middle Ages (Leipzig, 1855), praises Bartholomew for driving the demon out of Polymius' daughter. Dr. Norman Moore describes it as "A hymn contained in a manuscript old enough to have been read by our founder thus sums up the medical powers of our patron saint [Rahere]" (A Brief Relation of the Past and Present State of the Royal and Religious Foundation of St. Bartholomew's, (London: Adlard and Son) 1895).

In his joy at his daughter's recovery, Polymius attempted to reward Bartholomew with all the riches of the East. But the only reward Bartholomew wanted was the conversion of Polymius and his family and followers to the True Faith. In The Martyrdom, Bartholomew recounted tale after tale of Christ's life to the king, including the virgin birth -- Mary's redemption of Eve's sin -- and Christ's sacrifice on the Cross as the redemption of Adam's fall and the sins of all mankind. Finally, he emphasized the lesson in this way:
And when the Lord had conquered the tyrant [Satan], He sent His apostles into all the world, that He might redeem His people from the deception of the devil; and one of these I am, an apostle of Christ. On this account we seek not after gold or silver, but rather despise them, because we labour to be rich in that place where the kingdom of Him alone endures forever...

... At the same time hear also by what means he injures all those who are lying sick in the temple. The devil himself by his own art causes the men to be sick, and again to be healed, in order that they may the more believe in the idols, and in order that he may place the more in their souls, in order that they may say to the stock and the stone, You are our God. But that demon who dwells in the idol is held in subjection, conquered by me, and is able to give no response to those who sacrifice and pray there. And if you wish to prove that it is so, I order him to return into the idol, and I will make him confess with his own mouth that he is bound, and able to give no response.
Ironically, the argument which makes Bartholomew's final point, and converts Polymius, is offered by the demon Astaruth himself. Astaruth described the harrowing of Hell and Christ's resurrection, crying out "And he [Christ] put to death Death himself, our king, and he bound our prince [Satan] in chains of fire; and on the third day, having conquered death and the devil, rose in glory, and gave the sign of the cross to his apostles, and sent them out into the four quarters of the world; and one of them is here just now, who has bound me, and keeps me in subjection."

Polymius and his people converted to Christianity and tore down the idols and temples of their false worship. So far so good: Bartholomew gained the patronage of the king, and all seemed promising for the flourishing of the True Faith in this distant land. But we have failed to reckon with the priests of the false gods. Described only as Greeks, they fled to Polymius' brother, another king, named Astreges. Unfortunately the document fails to explain the political relationship between these two kings, which proves to be an important detail. Astreges questioned Bartholomew about his actions with regard to Astaruth, and incurs the apostle's wrath on his own patron diety, known as Baldad or Vualdath. At this point, Astreges orders his soldiers to beat the apostle with rods, and then behead him; as far as we know, Polymius had no way to prevent this punishment from being carried out:

The apostle says to him: If I have bound and kept in subjection the god which thy brother worshipped, and at my order the idols were broken in pieces, if thou also art able to do the same to my God, thou canst persuade me also to sacrifice to thy gods; but if thou canst do nothing to my God, I will break all thy gods in pieces; but do thou believe in my God.

And when he had thus spoken, the king was informed that this god Baldad and all the other idols had fallen down, and were broken in pieces. Then the king rent the purple in which he was clothed, and ordered the holy apostle Bartholomew to be beaten with rods; and after having been thus scourged, to be beheaded.

And innumerable multitudes came from all the cities, to the number of twelve thousand, who had believed in him along with the king; and they took up the remains of the apostle with singing of praise and with all glory, and they laid them in the royal tomb, and glorified God. And the king Astreges having heard of this, ordered him to be thrown into the sea; and his remains were carried into the island of Liparis.
Shortly after the apostle died, Astreges met an untimely end, being overpowered by a demon and strangled, as were his Greek priests. Polymius becomes a bishop and rules his people wisely for twenty years, having gained the power of healing himself.