Vasishta. Maharshis of Ancient India

Vasishta was one of the sapthabrahmas who were born of the mind of Brahma. He was the royal priest who was sought not only by great emperors but also by the Gods themselves. He was an ocean of knowledge as the Vedas, shastras, music and other arts were revealed to him as soon as he was born. His ashram was a center of holy and scholarly activities. People in and around his ashram received the fruits of the sage's tapas, his wife Arundathi's love, and the divine cow Shabale's bounty.
If Devendra appointed Vasishta as Brahma for a great yajna, Emperor Nimi and he cursed each other to die. The emperor died but the immortal sage assumed a new body. Under the sage's guidance, the kings of the solar clan shone as bright as the sun itself. Vasishta's advice to Emperor Dileepa to worship Nandini helped the royal couple to get a son thus averting a possible disaster of the solar line not having a successor.
The sage was forced into a duel with King Kaushika when the latter coveted the holy cow, Shabale. It was upon Vasishta's advice that Dasharatha agreed to send Rama and Lakshmana with Sage Viswamithra to assist him in the great yajna. The sage was instrumental in Ahalya being relieved of her husband's curse, in Rama getting married to Sita, in consoling Bharatha and making him agree to rule over Ayodhya during Rama's absence, and in conducting Rama's coronation after the death of Ravana.
King Saudasa who became Kalmashapada was subject to a series of curses. He killed all the sons of the sage due to which Vasishta tried to commit suicide. It was because of his grandson-son Shakthi and his wife Adrishyanthi's son Parashara-that he got renewed interest in life. When the period of Kalmashapada's curses were coming to an end , Vasishta forgot all about his misdeeds and blessed him to be a good king once again.
Brahmarishi Vasishta is truly a deathless sage and it's believed that he is still trying to establish the rule of law on earth.