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Parashara Rishi is a Rigvedic Maharishi and author of many ancient Indian texts.
There are several texts which give reference to Parashara Rishi as an author/speaker. The actual sage himself never wrote the texts, he was known as a preacher, and the various texts attributed to him are given in reference to Parashara Rishi being the speaker to his student.
It is difficult to be accurate about the period of Parashara Rishi but according to popular belief he belonged to the Mahabharata period which is estimated to be 3200 BC approximately. The depth of his astrological knowledge was so great of Parashara Rishi that, one day while crossing a river in a boat, he casually looked at his favourite stars in heaven, and suddenly realized that it was an exceptionally auspicious moment and if a child is conceived at that moment, he will be an expert in the Shastra's. So he told this to the lady rowing the boat and requested her to marry him.
She agreed and the son born was Veda Vyasa, who wrote 18 Puranas including the great epic Mahabharata, which includes
the famous Bhagavat Gita, the Brahma Sutras and the Uttara Mimansa and also authored Parashara Samhita and Parashara Smriti.