Rishi Panchami, which is occurs on the fifth day of the white half of the month of Bhaadrapada is dedicated to the seven seers of the Hindu Vedic tradition. Although Hinduism cannot claim one single founder or an event for its formation, credit is given to these seven seers who had heard the divine revelation of eternal truths whilst in deep meditation. These experiences in turn elevated their consciousness to a deeper spiritual level beyond material existence.
Although the seers are not explicitly mentioned during the earlier portion of the Vedas, they are however mentioned in the upaniṣads or later portions. There are differing opinions of the seven sages, however the bṛhadāraṇyakopaniṣat* mentions the seven as gotama, bharadvāja, viśvāmitra, jamadagnī, vasiṣṭha, kaśyapa and atri respectively.
As the revelations were merely heard by the seers they are known as the mantra drśtās and the revelation as śruti . The traditional view is that the revelations are anādi, apauruṣeya and nitya (beginningless, unauthored by man and eternal).
* bṛhadāraṇyakopaniṣat 2.2.4
(This article is taken from the Hinduism Crash Course Handbook)