The Yavanajataka, or 'Science of the Yavanas', was written by the Indo-Greek named "Yavanesvara" ("Lord of the Greeks") under the rule of the Western Kshatrapa king Rudrakarman I. The Yavanajataka written in 120 CE is often attributed to standardizing Indian astrology. The Navagraha would further develop and culminate in the Shaka era with the Saka, or Scythian, people. Additionally the contributions by the Saka people would be the basis of the Indian national calendar, which is also called the Saka calendar.