Hanuman Chalisa was composed by Gosvami Tulasidasa. He was a great devotee of Lord Ramachandra who lived in the 16th century. He composed the Rama-charita-manasa, the epic story of Lord Rama retold in the vernacular language. Many devotees regularly recite Hanuman Chalisa, a prayer glorifying Shri Hanuman, composed by this great saint and poet.
It is believed that in one of these verses of Hanuman Chalisa, Tulasidasa had given an accurate calculation of the distance between the Sun and Earth.
The Quest of Astronomers to find the distance of Sun