Sage Atri was one of the ten Maanas Putra (brainchild) of Brahma and one of the Saptarishis, the seven great sages. He was also a teacher of Ayurveda and father of Aatreya. His wife was Sati Anasuya, sister of Sage Kapila. As a boon from Lord Brahma, Vishnu and Shiva, she had Chandra, Dhattatreya and Durvasa as kids. Sage Atri was father of Sage Atteya Punarvasu, who was teacher of Caraka. Sage Atri was teacher of Ayurveda.

As per Ramayan’s Aranyakanda, Lord Rama along Sita Devi and Lakshman visited Atri muni and Sati Anasuya, wife of Atri gave a discourse on duties of wife to Sita Devi.

He had a close connection with Mahabharatha. We all know that Drona was made the head of the Kaurava army after Bhisma's fall. Dronacharya fought ferociously. The wounded and the dead soldiers was thousands. Their cry of pain rented the skies. Blood flowed on the battle field. Dead bodies got piled up and provided the food for the birds of prey. In this carnage which went beyond all human estimation, Drona stood like a mad hero of demonic proportion. Sage Atri was very much worried of this because if Drona continued this he would cause destruction and human misery beyond proportions, Atri and Gowthama came to the battle field along with their five of their companions. It was at this time Dharmaraja had shouted at the instance of Sri Krishna saying that Ashwathama was killed. This put Drona off completely. He lost all hope in his life. He became mad with anger. This sent danger signal all around. Sage Atri felt sad for him and talked to him in a friendly manner, consoling him, Dear friend, all along you have done everything against Dharma. This war you are engaged in is the best proof. It is enough and stop it. Stop this carnage. You are a good man. This act is not in tune with your status. You are a scholar of Vedanta par excellence. You have been a Brahman and you have got to practice dharma. This cruel act does not befit you. Give up your weapons, fix your mind in our glorious Sanathana Dharma. I am sorry, you have wielded the most terrible Brahmastra on the innocent soldiers! Put an end to your meaningless killing.
When Atri said that Dronacharya decided to give up his arms and stop killing. He drove away his anger jealousy and sense of revenge and his heart became pure. He sat in a yogic posture and started to meditate amidst the cries of pain, killing, flow of blood on the battle field. He concentrated on Lord Vishnu and closed his eyes and never opened them again until he left his body and started his journey towards the lord. Hence Sage Atri's kind nature helped to save man.

Lord Brahma’s ‘Manasa Putra’ (Mind-born son), Sage Atri performed a very powerful Sacrifice to Bhagavan Siva to bless a divinely son. The severity of the penance was such that the extreme heat from the Fire pit radiated all over the World and Devas approached Lord Brahma who along with Lord Vishnu conferred with Bhagavan Siva. They agreed with each other that they would all appear before Atri and blessed him to let Anasuya Devi ( Atri’s wife- a highly pious and chaste woman) conceive three boys, with the ‘Amsas’ ( partial manifestations) of all the three; from Brahma’s ‘amsa’ would emerge Chandra; Dattatreya as the manifestation of Maha Vishnu and Durvasa from Lord Siva. Indeed Anasuya (literally meaning Unenvious) had the unique distinction in the entire World of begetting three children with the ‘amsas’ of Tri Murtis!

Sage Atri was one of the ten Maanas Putra (brainchild) of Brahma and one of the Saptarishis, the seven great sages. He was also a teacher of Ayurveda and father of Aatreya. His wife was Sati Anasuya, sister of Sage Kapila. As a boon from Lord Brahma, Vishnu and Shiva, she had Chandra, Dhattatreya and Durvasa as kids.