ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

INDO-GREEK CONTACTS 7
accurate knowledge of the planetary motions earlier than about
the century of the Christian era. From thenceforth astronomy,
hitherto confined to rituals, appears as a science, treated in the
course of the next thousand years in a series of text-books,
the Siddhāntas,¹ the contents of which, though supposed to be
derived from divine sources are strongly influenced by Greek
authors. Prior to the Greek influence, we had ceremonies like
dvādaśāha (lasting for twelve days), ṣaḍaha (lasting for six days),
tryaha (lasting for three days) besides darśa-pūrṇamāsa ceremo-
nies connected with the New Moon and Full Moon. But the week
of seven days (Saptāha) was unknown in India. This concept of
week and the dedication of each day to the deity of one of the
seven planets, now appears for the first time. It is difficult to say
whether names of the planets were borrowed by Greeks from
India or vice versa, but they became common, e.g., Aśvajit or
Asphudit (Aphrodite), Dyugatiḥ or dyaus or Jīva (Zeus), Heli
(Helios), &c., while the zodiacal signs have superseded the earlier
but totally different twelve star-groups connected with the
Sun's motion, and proclaim their origin by their names:
Kriya, Tāvuri, Jituma, Karkin, Leya, Pāthena, Juka, Kaur-
pya, Taukshika, Ākokera, Hridroga, Ittha,
corresponding to Κριός, Ταῦρος, Δίδυμος, Καρκίνος, Λέων,
Παρθένος, Ζυγόν, Σκορπίος, Τοξότης, Αἰγόκερως, Ὑδροχόος,
Ἰχθύς².
A great many other Greek terms connected with geometry,
astronomy and astrology have also been transferred from Sans-
krit works to Greek and vice versa. This conclusively shows the
mutual influence on astronomy. Indian authors never failed to
acknowledge the ideas they borrowed from Greeks, e.g. Varāha-
mihira quotes the Yavanas or peoples of the west as authorities
for some of the scientific statements he makes. The name of the
Romaka Siddhānta (which is at least as old as A.D. 400) also
points in an unmistakable manner to its origin in one of the pro-
vinces of the Roman Empire.

1. The Romaka or Pauliśa Siddhānta (before 400 A. D.), See Varāhamihira's
   the Pañcasiddhāntikā (about 570 A.D., Varāhamihira died in 587 A.D.). The
   original Sūrya-siddhānta was prior to Varāhamihira, the modern edition is
   perhaps of the 13th century. See J. Burgess "Notes on Hindu Astronomy"
   J. R. A. S., October 1893, p. 742.