Sakas were Iranian-speaking horse nomads who deployed chariots in battle, sacrificed horses, and buried their dead in barrows or mound tombs called kurgans." The Sakas of Western India spoke the Saka language, also known as Khotanese as it was first attested in the Tarim Basin. Achaemenid period (6th-4th century BCE) During the Achaemenid conquest of the Indus Valley circa 515 BCE, the Achaemenid army was not uniquely Persian, and the Sakas probably participated in the invasion of northwestern India. The Achaemenid army was composed of many different ethnicities that were part of the vast Achaemenid Empire. The army included Bactrians, Sakas (Scythians), Parthians, and Sogdians. Herodotus gives a full list of the ethnicities of the Achaemenid army, in which are included Sakas together with Ionians (Greeks), and even Ethiopians. These ethnicities are likely to have been included in the Achaemenid army which invaded India. Some scholars, including Michael Witzel and Christopher I. Beckwith suggested that the Shakyas, the clan of the historical Gautama Buddha, were originally Scythians from Central Asia, and that the Indian ethnonym Śākya has the same origin as “Scythian”, called Sakas in India. This would also explain the strong support of the Sakas for the Buddhist faith in India. The Persians, the Sakas and the Greeks, may have later participated in the campaigns of Chandragupta Maurya to gain the throne of Magadha circa 320 BCE. The Mudrarakshasa states that after Alexander's death, an alliance of "Shaka-Yavana-Kamboja-Parasika-Bahlika" was used by Chandragupta Maurya in his campaign to take the throne in Magadha and found the Mauryan Empire. The Sakas were the Scythians, the Yavanas were the Greeks, and the Parasikas were the Persians. Yuezhi expansion (2nd century BCE) In the 2nd century BCE, a fresh nomadic movement started among the Central Asian tribes, producing lasting effects on the history of Rome in Europe, Parthia in Western Asia, and Bactria, Kabul, and India in the east in Southern Asia. Recorded in the annals of the Han dynasty and other Chinese records, this great tribal movement began after the Yuezhi tribe was defeated by the Xiongnu, fleeing westwards after their defeat and creating a domino effect as they displaced other central Asian tribes in their path. According to these ancient sources Modu Shanyu of the Xiongnu tribe of Mongolia attacked the Yuezhi (possibly related to the Tocharians who lived in eastern Tarim Basin area) and evicted them from their homeland between