There seem to have been a conflict of Eras at the time when Aryabhata flourished. There was the Malava Era in Western Malwa, the Gupta Km known in the Gupta Empire, the Saka Era, the Kalacuri Era and so on all local and tribal eras.
Aryabhatta is the first writer on astronomy to whom the Hindus do not allow the honour of a divine inspiration. Writers on mathematical science distinctly state that he was the earliest uninspired and a merely human writer on astronomy. This is a notice which sufficiently proves his being an historical character.
The chief doctrines which Aryabhatta professed were that he He affirmed the diurnal revolution of the earth on its axis; an assertion which is fully borne out by a quotation from one of his works, in a commentary on the "Brahmasphut'a-Siddhanta" of Brahmagupta by Prithudakaswami: "The Earth making a revolution produces a daily rising and setting of the stars and planets". Aryabhatta is said to have discovered the diurnal motion of the earth' which he thought to be spherical.
Aryabhatta had another celebrated astronomer known as Varahamihira as his contemporary.
Aryabhatta also ascribed to the epicycles, by which the motion of a planet is represented, a form varying from the circle and nearly elliptic.
Aryabhata wrote his Kala-kriya (calculation of time) here at the age of 23 that is, 499 A.D.
ARYABHATTA was author of the Arykshiasata (800 couplets) and Dasagi-tica (ten stanzas), known by the numerous quotations of BRAHMEGUPTA, BHAT'TATPALA, and others, who cite both under these respective titles.
ARYABHATTA’S text specifies the earth's diameter, 1050 yojanas; and the orbit or circumference of the earth's wind [spiritus vector] 3393 yojanas; which, as the scholiast rightly argues, is no discrepancy.
UNDER the Abbasside Khalifs ALMANSU'R and ALMAMUN, in the middle of the eighth and beginning of the ninth centuries of the Christian era, the Arabs became conversant with the Indian astronomy.
