Aryabhata's compact 5th-century text of astronomical and mathematical verses — the origin point for a value of pi, a rotating earth, and a systematic explanation of eclipses within the tradition.
४९९ ई. · 499 CE
Written in only 121 verses across four sections, the Aryabhatiya compresses arithmetic, algebra, trigonometry, and planetary astronomy into an extremely dense verse form meant to be memorized, in keeping with the era's oral transmission of technical knowledge.
Its influence reached beyond the subcontinent through translation into Arabic by the 8th century, feeding into the broader medieval transmission of mathematical and astronomical knowledge across the Islamic world and eventually into Europe. Aryabhata himself is covered separately in this site's Rishi Parampara chapter.