The modern sine convention is first attested in the Surya Siddhanta (showing strong Hellenistic influence)^[64], and its properties were further documented by the 5th century (CE) Indian mathematician and astronomer Aryabhata.^[60] The Surya Siddhanta describes rules to calculate the motions of various planets and the moon relative to various constellations, diameters of various planets, and calculates the orbits of various astronomical bodies. The text is known for some of earliest known discussion of sexagesimal fractions and trigonometric functions.^[61]