The curse of Sarasvatī
Sarasvatī, Gaṅgā and Lakṣmī were all, in the beginning, wives of Mahāviṣṇu. The Lord loved all the three equally. One day all the four were sitting together when Gaṅgā sent lustful glances at Viṣṇu which was immediately noticed by both Sarasvatī and Lakṣmī. Sarasvatī got angry and rising up caught hold of the hair of Gaṅgā and dragged her to the ground. Lakṣmī then caught hold of Sarasvatī to prevent further assault but Sarasvatī then poured all her rage on Lakṣmī and cursed her to be born as a plant on earth. Gaṅgādevī could not bear this and she cursed Sarasvatī to be born as a river on earth. Sarasvatī retorted with a curse that Gaṅgā also would be born as a river. When the whole tumult was over Viṣṇu called Lakṣmī to his side and said "Oh Devī, do not worry. Things have happened as predestined. You go and be born as the daughter of Dharmadhvaja and grow up there. From there by divine grace you will be transformed into a plant sacred enough to make all the three worlds pure. That plant will be named Tulasī. When you will be thus living as Tulasī, a demon named Śaṅkhacūḍa with part of rny virile strength will be born and he will marry you. Then you can come back to me. The holy river Padmāvatī will also be another form of your spirit."
The story of Dharmadhvaja
Who was this Dharmadhvaja to whom was born Mahālakṣmī as a daughter? In times of old there was a Manu called Dakṣasāvarṇi who was extremely virtuous and a part of Viṣṇu. Descending from Dakṣasāvarṇi were Brahmasāvarṇi Dharmasāvarṇi-Rudrasāvarṇi-Devasāvarṇi-Indrasāvarṇi Vṛṣadhvaja. This last named was a great devotee of Śiva and because of his great affection for this devotee Śiva lived a whole period of a deva-yuga in the āśrama of Vṛṣadhvaja. King Vṛṣadhvaja by an edict prohibited the worship of any other deity than Śiva in his country. Even the worship of Mahālakṣmī ordained by the Vedas during the month of Bhādra (September) became extinct. All Yagas and worship of Viṣṇu came to a stop. Sūrya (Sun-god) got angry at this belittling of other gods than Śiva and cursed the King Vṛṣadhvaja that he would cease to be prosperous. Śiva did not like it and he went to punish Sūrya holding his trident in his hand. Sūrya was frightened and he approached his father Kaśyapa. Kaśyapa and Sūrya went to Brahmā and acquainted him with all details. Brahmā also was helpless in the matter and so all the three of them went to Mahāviṣṇu. They prostrated before Viṣṇu and told him all. At that time Śiva also came there. Addressing all of them Viṣṇu said "Oh, Devas, within this half an hour twentyone yugas have passed by on the earth. He about whom you have come to speak to me is dead and gone. Even his son Rathadhvaja is dead. The latter has two sons named Dharmadhvaja and Kuśadhvaja. They are dull and splendourless now because of the curse of Sūrya and are now worshipping Lakṣmī" Saying thus Viṣṇu disappeared.
Birth of Tulasī
Dharmadhvaja and Kuśadhvaja did penance to propitiate Mahālakṣmī. Kuśadhvaja had a wife named Mālāvatī. She bore a daughter named Vedavatī. Sītā, wife of Śrī Rāma, was a rebirth of this Vedavatī. King Dharmadhvaja had a wife named Mādhavī. Mahālakṣmī entered her womb as an embryo and after a hundred years Mādhavī gave birth to a daughter. Even at the time of birth the child looked like a matured girl and was extremely pretty. She was therefore, called Tulasī, meaning matchless. (Tula = match). This Tulasī abandoning all worldly pleasures went to Badarikāśrama and started doing penance there with the prayer that Mahāviṣṇu should become her husband. She did penance for twentyfour thousand years sitting amidst fire in the hot season and sitting in water in the cold season and taking only fruits and water as food. Then she did penance for another thirtythousand years eating leaves only, another forty thousand years taking air only as food and another ten thousand years without any food. At this stage Brahmā appeared and asked her the object of her Penance. She replied she wanted Mahāviṣṇu to be her husband. Hearing this Brahmā said thus "Devi, you know the cowboy Sudāmā born of a part of Śrī Kṛṣṇa. That brilliant cowboy has now been born on earth, due to a curse of Rādhā, as a demon named Śaṅkhacūḍa. He is matchlessly eminent and has once fallen in love with you seeing you at Goloka. You will become his wife and later you can become the wife of Nārāyaṇa. At that time a part of your divine body will remain on earth as a plant named Tulasī. Tulasī will become the most sacred of all plants, dear to Viṣṇu, and all worship without using Tulasī leaves would be ineffective."
Marriage of Tulasī
Due to a curse of Rādhā, Sudāma, the cowboy, was born on earth as a demon named Śaṅkhacūḍa. He did penance sitting at Badarikāśrama and obtained Viṣṇukavaca. Another object of his was to marry Tulasī. He obtained a boon from Brahmā that his death would occur only when the Viṣṇu Kavaca was removed from his body and the chastity of his wife was lost. At that time Śaṅkhacūḍa and Tulasī met each other in the forests and were married. Śaṅkhacūḍa, brilliant and majestic, went about with Tulasī in amorous sports creating jealousy even among the devas. His arrogance gave innumerable troubles to the devas and they along with Brahma and Śiva approached Mahāviṣṇu for a remedy. Viṣṇu then sent Śiva with his spike to kill Śaṅkhacūḍa and he himself started to molest the chastity of his wife Tulasī. Saiikhacuda took leave of Tulasī to go and fight with Śiva. When Tulasī was thus left alone, Mahāviṣṇu in the form of Śaṅkhacūḍa approached Tulasī and after some preliminary talks entered into sexual acts. Tulasī found some difference in the usual sexual methods and suspecting foul play jumped up to curse the impostor. At once Mahāviṣṇu appeared in his true form and said "You have been doing penance for a long time to get me as your husband. Your husband Śaṅkhacūḍa was the chief of my Pārṣadas, Sudāma. It is time for him to go back to Goloka getting himself released from the curse. By this time Śiva would have killed him and he would have gone to Goloka as Sudāma. You can now abandon your body and come with me to Vaikuṇṭha to enjoy life as my wife. Your body will decay and become a holy river named Gaṇḍakī: your hair will become Tulasī plant the leaves of which will be held sacred in all the three worlds." Tulasī then changed herself into the form of Lakṣmī and went to Vaikuṇṭha with Mahāviviṣṇuu. (9th Skandha, Devī Bhāgavata).
The greatness of Tulasī
Everything of the Tulasī plant, leaves, flowers, fruits, roots, twigs, skin and even the soil around is holy. The soul of a dead one whose dead body is cremated using Tulasī twigs for firewood would attain a permanent place in Viṣṇuloka. Even great sinners would be absolved of their sins if their dead bodies are cremated with Tulasī twigs. If at the time of death one thinks of God and mutters His name and if his dead body is later cremated with Tulasī twigs, he would have no rebirths. Even he who has done a crore of sins would attain moksa if at the time of cremating his dead body a piece of Tulasī twig is placed at the bottom of the funeral pyre. Just as all waters become pure by the union with Gaṅgā water, all firewood is made pure by the addition of a small piece of Tulasī twig. If the dead body of one is cremated using Tulasī twigs alone, one's sins for a crore of Kalpa years would be washed away. Yamadūtas would keep away from one whose dead body is cremated with Tulasī twigs and servants of Viṣṇu would come near. If a light is burnt for Viṣṇu with a Tulasī stick it would be equal to burning several lakhs of lights for Viṣṇu. If one makes the Tulasī leaves into a paste and smears it on one's body and then worships Viṣṇu for one day, one would be getting the benefit of a hundred ordinary worships and also the benefit of doing a hundred godanas. (gifts of cows). (Chapter 24, Padma Purāna).