Varahamihira's Five: Synthesizing World Astronomy

How a 6th-century scholar at Ujjain laid five rival astronomies side by side and built the first comparative science

In 575 CE Varahamihira wrote the Panchasiddhantika, a line-by-line comparison of five competing astronomical systems including Greek and Roman ones, ranked by accuracy and synthesized into a single working tradition. This lesson shows why that book is one of the earliest surviving works of comparative science anywhere in the world.

Five Skies on One Desk

In the middle of the sixth century CE, in the astronomical observatory on the banks of the Kṣiprā river at Ujjain, the court mathematician Varāhamihira sat down with five astronomical treatises laid out in front of him. Each gave a different length for the year. Each gave different periods for the planets. Each gave different rules for predicting eclipses. One, the Paitāmaha, was attributed to the ancient grandfather Brahmā. One, the Vāsiṣṭha, to the sage of that name. One, the Romaka, had come to India by sea from Alexandria and the eastern Roman empire and was spoken of at Ujjain in a technical vocabulary half-Sanskrit and half-Greek. One, the Pauliśa, carried the name of a teacher the later Persian scholar al-Bīrūnī would identify with the Alexandrian astronomer Paul. The fifth, the Sūrya, was a fresh Indian recension of older material that would later become canonical. Five rival systems. Five different skies. A working astronomer in a temple town could not use all five. He had to choose, or he had to reconcile.

Varāhamihira did the hardest thing. He laid the five side by side, ranked them against observation, and wrote a synthesis. The resulting work, the Pañcasiddhāntikā, the Treatise on the Five Siddhāntas, is one of the earliest surviving works of comparative science anywhere in the world, and it is the single reason Indian astronomy after his time was more accurate than any of its individual sources.

Who He Was

Varāhamihira lived from roughly 505 to 587 CE, most of his working life spent at Ujjain, the astronomical and mathematical capital of classical India. Tradition places him as one of the Navaratnas, the nine jewels, at the court of a king called Vikramāditya. The historicity of the title is debated, but the mathematical record is not. Varāhamihira produced three major works that any serious student of Indian science still has to read. The Pañcasiddhāntikā on mathematical astronomy. The Bṛhat Saṃhitā, an encyclopedia of natural science, civil engineering, meteorology, gem-craft, and astronomy-adjacent topics. And the Bṛhajjātaka, the canonical Indian text on horoscopy. The first is our subject here.