Near Mithila, there lived in an ashram a Maharishi named Katyayana. He had a daughter named Katyayani. She was very beautiful and intelligent. She was proficient in many branches of learning. She attained marriageable age. Maharishi Katyayana was very anxious to give away his daughter to a versatile young man. He came to know of Yagnavalkya's greatness and went to him and offered her daughter in marriage. Yagnavalkya accepted the offer and the marriage was conducted in an auspicious day. The couple led an ideal life of enjoyment, happiness, contentment and peace. In the course of time Katyayani presented Yagnavalkya with four sons and they were named Katyayana, Chandrakanta, Mahamedha and Vijaya. All these sons in their own time became great scholars and renowned for their knowledge in Vedas and Sastras.

In the town of Janakpur, near the city of Mithila, assisting King Janaka as a minister was a learned Vedic scholar and sage name Mitra. He had an accomplished and extremely beautiful daughter called Maitreyi. As she was growing up, Maitreyi came under the influence of her maternal aunt, the erudite Vedic scholar Gargi. Because of her intimate association and close contact with her aunt Maitreyi cultivated a thirst for theological truths and was interested in gaining knowledge of the Vedas, Upanishads and Sastras. Thereafter Maitreyi was spending a good deal of time with Gargi and was getting trained under her.

It was because of Maitreyi's keen interest in philosophical knowledge that Gargi took her niece to the Yagna of Janaka. Maitreyi observed with keen interest the superlative wisdom and incisive intellect of Yagnavalkya and the manner and mastery of his clear exposition of the highest philosophy of Brahma-Jnana. Maitreyi felt at once drawn towards him when he vanquished Maharishi after Maharishi, with cogent rational arguments, demolishing their reasoning and exposing their deficiency of knowledge. Maitreyi, who had known Yagnavalkya as the husband of her friend Katyayani, developed a sort of personal affection towards Yagnavalkya. She realised that to acquire a true knowledge of the Vedas, Upanishads and Sastras, there was no better preceptor and teacher than Yagnavalkya. She decided then and there to become Yagnavalkya's direct disciple. However she felt there was a problem in becoming a sishya. As she was a spinster of age 18 it would be unthinkable to become a sishya in the gurukulam and hence, she thought the only way to attain her objective is to marry Yagnavalkya.
Since Yagnavalkya was already married to Katyayani who was very close to her as they were family friends she hesitated how to pursue this idea. She felt the only way she could succeed was to get the agreement of Katyayani for the proposal.

With the consent of her parents she went, along with Gargi, to Katyayani and dwelt in detail her objective of learning from the great sage and she said the only way was to become the second wife. She requested Katyayani to grant her the boon and consent for the marriage. Katyayani, realising Maitreyi's bent of mind, appreciated the purpose behind Maitreyi's desire and felt called upon to accede to her request. The charitable lady she was, she even went to the extent of placing this proposal before her husband. There was a long discussion between the wife and the husband in which Yagnavalkya questioned Katyayani whether she would not become envious and jealous of Maitreyi in due course. After ascertaining the sincerity of the Katyayani, Yagnavalkya acceded to the request and took Maitreyi as his second wife.

Yagnavalkya, Katyayani and Maitreyi settled down to lead a life of peace and quiet. He was regular in performing daily rites precisely and punctually in accordance with Sastraic tenets. In this both his wives were assisting him in several ways. In the evenings, Yagnavalkya, Katyayani and Maitreyi used to discuss many purely metaphysical subjects.

Katyayani was an ideal and virtuous housewife, attending to domestic duties and household chores in the traditional way. She looked after the needs of the family and her husband. Katyayani was adept in cooking. She attended on her husband, relatives and also guests with great respect and reverence due to each of them.

Maitreyi was pre-eminent among women scholars. She was a seeker of knowledge and had realised early in life, the ephemeral and false nature this phenomenal existence. She was dispassionately devoid of all the usual worldly worries and the common cares that confront human beings. She was constantly making self-inquiries of introspection. Yet Yagnavalkya bade her to engage herself in household work, so that she may pass through the mill of a householder and be aware of the relative duties of a wife in grahasthasrama.

Yagnavalkya was frequently retiring to secluded spots in and around his ashrama and was often found ruminating about all aspects of the purport of human existence and the best ways of achieving fulfillment. He used to cogitate constantly the futility of human existence and was convinced that all the pleasures of life and enjoyments experienced by this physical body are only a result of the mental vritti and imagination of one's own innate ignorance and lack of knowledge of the reality. At the same time he also felt himself in a state of exhilarating exuberance in realizing the non-dual blissful Atman dwelling permanently in the inner recesses of his heart. He also perceived a sense of thankfulness for his illustrious preceptor, the Surya Bhagavan for having bid him to disseminate the intricate knowledge of Shukla Yajur Veda. He derived the comfort that he had carried out the injunctions of his divine teacher in imparting in his turn to several disciples. Yagnavalkya himself was engaged in evolving and codifying the thought provoking Yagnavalkya Smriti, the bedrock foundation and corner stone of the edifice of common law and jurisprudence. Yagnavalkya felt called upon to retire from the blaze of public glory and assume the order of sanyasins.

The scriptures prescribe that those belonging to first three varnas of society i.e., Brahmana, Kshatriya and Vaisya, should remain within the four orders of life. They are (i) the life of a brahmacharya, a student (ii) the life of a grahastha or domestic life (iii) the life of a vanaprastha or life of retirement in the forest and (iv) the life of an ascetic or sanyasin. The elders have formulated the proper time and circumstances as to when a householder should enter forest life by laying down that one should have grown gray and old with wrinkles and become a grand father through his son begetting a son.

Yagnavalkya, though a knower of Brahman and had attained a knowledge of the Supreme Being was yet under an obligation to secure clearance from the three kinds of debts pertaining to a householder i.e. the debts due to the Sages, Saints and Rishis, the debts due to celestials (Devas) and debts due to ancestors. He had already cleared his debt to Sages by learning the Vedas and sastras and chanting Vedas regularly. He cleared his debts to celestials by conducting daily sacrifices and other rituals as enjoined in the Vedas. He cleared the third debt by offering libation to his ancestors through performance of rituals and sacrifices to his departed ancestors. Thus he was fully qualified to enter Sannyasa. Yagnavalkya deeply pondered how his two wives would react to his decision. He felt that Katyayani being of a simple dutiful person devoted to family might agree to the decision if adequate arrangements are made to take of future welfare. However he was doubtful about how Maitreyi would react. As expected Katyayani accepted Yagnavalkya's decision whereas Maitreyi had a long discussion with Yagnavalkya the reason and objective of the sannyasa ashrama. At the end of the discussion she was convinced that she too should take to Sannyasa to attain true knowledge!

Yagnavalkya after imparting the knowledge of Atman to his wife Maitreyi renounced the life of a grahastha and embraced sannyasa. Yagnavalkya transformed himself into a jivan mukta and was traversing from place to place and imparting knowledge to everybody. Maitreyi took to the life of acetic herself and was moving about from one place to another. In accordance with the sanctions of Scriptures she was not wearing the outer insignia of sanyasin even though she was observing the prescribed spiritual practices like celibacy, living on alms and charities etc. A great Vedantin she was, Maitreyi later on composed the great Maitreyi Upanishad, a signal contribution to the world of theology.

It was a great credit to Yagnavalkya as he was the very first to take to Sannyasa and came to be known as "Prime Sanyasin". He made the unique contribution to Hindu Dharma with his espousal of the spiritual and ethical importance of sannyasa ashrama. The Brihadaranyaka Upanishad is replete with clear directions for attaining the sannyasa ashrama. The Jabalopanishad belonging to the Shukla Yajur Veda also expounds and explains the guidelines for taking the sannyasa ashrama direct from brahmacharya. In fact, Adi Sankara observed the procedure outlined in this Upanishad when he took to sannyasa ashrama.