Brahmagupta
Brahmagupta (596-668 AD) was a mathematician and astronomer, the first to use the zero as one of the natural numbers. To him are owed the first demonstrations of numerous theorems in algebra, arithmetic, geometry, and the theory of diophantine equations. His treatise on astronomy, the Brāhmasphuṭasiddhānta (‘Extensive Treatise of Brahma’) of 628 was the principal source of Indian astronomy in the Arab world and an important influence on all of Arabic astronomy. In it he argued that the Earth is spherical and in motion.
Links
Wilbourhall.org. Brahmagupta, the Brāhmasphutasiddhānta, English introduction >