Aryabhata was an ancient Indian philosopher and astronomer who made a wide variety of contributions, including approximating the value of Pi, asserting that the Earth makes a daily rotation on an axis and describing rules for eclipse calculations. He wrote numerous books in his lifetime, many of which are believed to be lost. He lived from about 476 to 550 A.D.
In addition to approximating Pi's value, Aryabhata is believed to have first defined the number as irrational. He also developed formulas for calculating the area of shapes like triangles, leaving a strong mark on geometry, and his trigonometric contributions include a sine table that, like his other work, was written in verse. Not only was Aryabhata a mathematician and scientist, but he also had a talent for words.
Aryabhata's contributions to astronomy are also significant; these contributions include counting solar days, determining the Earth's spherical shape and making a nearly accurate prediction of the Earth's circumference. He was also a pioneer in predicting the source of the moon's light; he correctly asserted that the moon itself doesn't generate light but rather reflects light from the sun. This is all quite impressive considering that Aryabhata lived more than a thousand years before the earliest telescopes were developed in Europe.