Skandha-Traya: Three Branches, One Tradition

Understanding Siddhānta, Horā, and Saṃhitā as distinct but related disciplines

Explore the three skandhas (branches) of Jyotiṣa: mathematical astronomy (Siddhānta), predictive astrology (Horā), and mundane astrology (Saṃhitā), and understand how the tradition itself named and separated them.

The Man Who Wrote Three Books

In the sixth century, in the city of Ujjain, a scholar named Varāhamihira sat down to organise everything his civilization knew about the sky.

Ujjain was the right place for it. The city stood on what Indian astronomers treated as the prime meridian, the zero-line from which they measured the heavens, close enough to the Tropic of Cancer that the midsummer noon sun stood almost straight overhead. Varāhamihira worked there among the scholars of a brilliant court, writing on dried palm-leaf in a dense, verse-packed Sanskrit.

What he produced was staggering in range. He wrote the Pañcasiddhāntikā, a work of hard planetary mathematics that gathered five older astronomical schools into one. He wrote the Bṛhat Jātaka, a manual of horoscopy. And he wrote the Bṛhat Saṃhitā, a sprawling encyclopaedia that ran from the paths of comets to the building of houses, from the signs of coming rain to the cutting of gemstones. One man, three books, three completely different kinds of knowledge.

Which raises the question this lesson answers: what were these three things doing under a single name, and how did the tradition tell them apart?

Three Branches on One Trunk

Varāhamihira gave the answer in a single dense verse, and it is worth meeting in his own words.

ज्योतिःशास्त्रमनेकभेदविषयं स्कन्धत्रयाधिष्ठितं तत्कार्त्स्न्योपनयस्य नाम मुनिभिः सङ्कीर्त्यते संहिता। स्कन्धेऽस्मिन्गणितेन या ग्रहगतिस्तन्त्राभिधानस्त्वसौ होरान्योऽङ्गविनिश्चयश्च कथितः स्कन्धस्तृतीयोऽपरः॥

jyotiḥśāstram aneka-bheda-viṣayaṃ skandha-trayādhiṣṭhitaṃ tat-kārtsnyopanayasya nāma munibhiḥ saṅkīrtyate saṃhitā skandhe'smin gaṇitena yā graha-gatis tantrābhidhānas tv asau horānyo'ṅga-viniścayaś ca kathitaḥ skandhas tṛtīyo'paraḥ

The science of the heavenly lights, vast in its subjects, rests upon three branches. The complete treatment of the whole of it, the sages call Saṃhitā. Within it, the planetary motion reckoned by calculation is named Tantra; another branch is Horā, the fixing of the parts of the birth-chart; and the third branch is declared to be the remaining one.

Varāhamihira, Bṛhat Saṃhitā 1.9