Before the creation started, Lord Brahma needed a few people who can be held responsible for the creation of the remaining Universe. Therefore he created 10 Prajapatis (Ruler of the people) from his Manas (Mind) and 9 from his body. Marichi is one of the manasaputras of Lord brahma. The 10 Prajapatis are as follows:
^Inhabitants of the Worlds Mahanirvana Tantra, translated by Arthur Avalon, (Sir John Woodroffe), 1913, Introduction and Preface. The Rishi are seers who know, and by their knowledge are the makers of shastra and "see" all mantras. The word comes from the root rish Rishati-prapnoti sarvvang mantrang jnanena pashyati sangsaraparangva, etc. The seven great Rishi or saptarshi of the first manvantara are Marichi, Atri, Angiras, Pulaha, Kratu, Pulastya, and Vashishtha. In other manvantara there are other sapta-rshi. In the present manvantara the seven are Kashyap, Atri, Vashishtha, Vishvamitra, Gautama, Jamadagni, Bharadvaja. To the Rishi the Vedas were revealed. Vyasa taught the Rigveda so revealed to Paila, the Yajurveda to Vaishampayana, the Samaveda to Jaimini, Atharvaveda to Samantu, and Itihasa and Purana to Suta. The three chief classes of Rishi are the Brah-marshi, born of the mind of Brahma, the Devarshi of lower rank, and Rajarshi or Kings who became Rishis through their knowledge and austerities, such as Janaka, Ritaparna, etc. Thc Shrutarshi are makers of Shastras, as Sushruta. The Kandarshi are of the Karmakanda, such as Jaimini.