Check out the full story from our homeboy Thomas Bulfinch:
BACCHUS was the son of Jupiter and Semele. Juno, to gratify her resentment against Semele, contrived a plan for her destruction. Assuming the form of Beroe, her aged nurse, she insinuated doubts whether it was indeed Jove himself who came as a lover. Heaving a sigh, she said, "I hope it will turn out so, but I can't help being afraid. People are not always what they pretend to be. If he is indeed Jove, make him give some proof of it. Ask him to come arrayed in all his splendours, such as he wears in heaven. That will put the matter beyond a doubt." Semele was persuaded to try the experiment. She asks a favour, without naming what it is. Jove gives his promise, and confirms it with the irrevocable oath, attesting the river Styx, terrible to the gods themselves. Then she made known her request. The god would have stopped her as she spake, but she was too quick for him. The words escaped, and he could neither unsay his promise nor her request. In deep distress he left her and returned to the upper regions. There he clothed himself in his splendours, not putting on all his terrors, as when he overthrew the giants, but what is known among the gods as his lesser panoply. Arrayed in this, he entered the chamber of Semele. Her mortal frame could not endure the splendours of the immortal radiance. She was consumed to ashes.
Jove took the infant Bacchus and gave him in charge to the Nysaean nymphs, who nourished his infancy and childhood, and for their care were rewarded by Jupiter by being placed, as the Hyades, among the stars. When Bacchus grew up he discovered the culture of the vine and the mode of extracting its precious juice; but Juno struck him with madness, and drove him forth a wanderer through various parts of the earth. In Phrygia the goddess Rhea cured him and taught him her religious rites, and he set out on a progress through Asia, teaching the people the cultivation of the vine. The most famous part of his wanderings is his expedition to India, which is said to have lasted several years. Returning in triumph, he undertook to introduce his worship into Greece, but was opposed by some princes, who dreaded its introduction on account of the disorder and madness it brought with it.
As he approached his native city Thebes, Pentheus the king, who had no respect for the new worship, forbade its rites to be performed. But when it was known that Bacchus was advancing, men and women, but chiefly the latter, young and old, poured forth to meet him and to join his triumphal march.
It was in vain Pentheus remonstrated, commanded and threatened. "Go," said he to his attendants, "seize this vagabond leader of the rout and bring him to me. I will soon make him confess his false claim of heavenly parentage and renounce his counterfeit worship." It was in vain his nearest friends and wisest counsellors remonstrated and begged him not to oppose the god. Their remonstrances only made him more violent.
But now the attendants returned whom he had despatched to seize Bacchus. They had been driven away by the Bacchanals, but had succeeded in taking one of them prisoner, whom, with his hands tied behind him, they brought before the king. Pentheus, beholding him with wrathful countenance, said "Fellow! you shall speedily be put to death, that your fate may be a warning to others; but though I grudge the delay of your punishment, speak, tell us who you are, and what are these new rites you presume to celebrate."
The prisoner, unterrified, responded, "My name is Acetes; my country is Maeonia; my parents were poor people, who had no fields or flocks to leave me, but they left me their fishing rods and nets and their fisherman's trade. This I followed for some time, till growing weary of remaining in one place, I learned the pilot's art and how to guide my course by the stars. It happened as I was sailing for Delos we touched at the island of Dia and went ashore. Next morning I sent the men for fresh water, and myself mounted the hill to observe the wind; when my men returned bringing with them a prize, as they thought, a boy of delicate appearance, whom they had found asleep. They judged he was a noble youth, perhaps a king's son, and they might get a liberal ransom for him. I observed his dress, his walk, his face, There was something in them which I felt sure was more than mortal. I said to my men, 'What god there is concealed in that form I know not, but some one there certainly is. Pardon us, gentle deity, for the violence we have done you, and give success to our undertakings.' Dictys, one of my best hands for climbing the mast and coming down by the ropes, and Melanthus, my steersman, and Epopeus, the leader of the sailor's cry, one and all exclaimed, 'Spare your prayers for us.' So blind is the lust of gain! When they proceeded to put him on board I resisted them. 'This ship shall not be profaned by such impiety,' said I. 'I have a greater share in her than any of you.' But Lycabas, a turbulent fellow, seized me by the throat and attempted to throw my overboard, and I scarcely saved myself by clinging to the ropes. The rest approved the deed.
"Then Bacchus (for it was indeed he), as if shaking off his drowsiness, exclaimed, 'What are you doing with me? What is this fighting about? Who brought me here? Where are you going to carry me?' One of them replied, 'Fear nothing; tell us where you wish to go and we will take you there.' 'Naxos is my home,' said Bacchus; 'take me there and you shall be well rewarded.' They promised so to do, and told me to pilot the ship to Naxos. Naxos lay to the right, and I was trimming the sails to carry us there, when some by signs and others by whispers signified to me their will that I should sail in the opposite direction, and take the boy to Egypt to sell him for a slave, I was confounded and said, 'Let some one else pilot the ship;' withdrawing myself from any further agency in their wickedness. They cursed me, and one of them, exclaiming, 'Don't flatter yourself that we depend on you for our safety,' took my place as pilot, and bore away from Naxos.
"Then the god, pretending that he had just become aware of their treachery, looked out over the sea and said in a voice of weeping, 'Sailors, these are not the shores you promised to take me to; yonder island is not my home. What have I done that you should treat me so? It is small glory you will gain by cheating a poor boy.' I wept to hear him, but the crew laughed at both of us, and sped the vessel fast over the sea. All at once- strange as it may seem, it is true,- the vessel stopped, in the mid sea, as fast as if it was fixed on the ground. The men, astonished, pulled at their oars, and spread more sail, trying to make progress by the aid of both, but all in vain. Ivy twined round the oars and hindered their motion, and clung to the sails, with heavy clusters of berries. A vine, laden with grapes, ran up the mast, and along the sides of the vessel. The sound of flutes was heard and the odour of fragrant wine spread all around. The god himself had a chaplet of vine leaves, and bore in his hand a spear wreathed with ivy. Tigers crouched at his feet, and forms of lynxes and spotted panthers played around him. The men were seized with terror or madness; some leaped overboard; others preparing to do the same beheld their companions in the water undergoing a change, their bodies becoming flattened and ending in a crooked tail. One exclaimed, 'What miracle is this!' and as he spoke his mouth widened, his nostrils expanded, and scales covered all his body. Another, endeavouring to pull the oar, felt his hands shrink up and presently to be no longer hands but fins; another, trying to raise his arms to a rope, found he had no arms, and curving his mutilated body jumped into the sea. What had been his legs became the two ends of a crescent-shaped tail. The whole crew became dolphins and swam about the ship, now upon the surface, now under it, scattering the spray, and spouting the water from their broad nostrils. Of twenty men I alone was left. Trembling with fear, the god cheered me. 'Fear not,' said he; 'steer towards Naxos.' I obeyed, and when we arrived there, I kindled the altars and celebrated the sacred rites of Bacchus."
Pentheus here exclaimed, "We have wasted time enough on this silly story. Take him away and have him executed without delay." Acetes was led away by the attendants and shut up fast in prison; but while they were getting ready the instruments of execution the prison doors came open of their own accord and the chains fell from his limbs, and when they looked for him he was nowhere to be found.
Pentheus would take no warning, but instead of sending others, determined to go himself to the scene of the solemnities. The mountain Citheron was all alive with worshippers, and the cries of the Bacchanals resounded on every side. The noise roused the anger of Pentheus as the sound of a trumpet does the fire of a war-horse. He penetrated through the wood and reached an open space where the chief scene of the orgies met his eyes. At the same moment the women saw him; and first among them his own mother, Agave, blinded by the god, cried out, "See there the wild boar, the hugest monster that prowls in these woods! Come on, sisters! I will be the first to strike the wild boar." The whole band rushed upon him, and while he now talks less arrogantly, now excuses himself, and now confesses his crime and implores pardon, they press upon him and wound him. In vain he cries to his aunts to protect him from his mother. Autonoe seized one arm, Ino the other, and between them he was torn to pieces, while his mother shouted, "Victory! Victory! we have done it; the glory is ours!"
So the worship of Bacchus was established in Greece.