We are talking about the Syr Darya in Central Asia. It is sometimes called «Yaksart» by the name 'iαρατις in ancient Greek. The Greek name for the river originates from the ancient Persian phrase Yakhsha Arta («large margin»), which was formed from the color of the river’s water. In medieval Muslim records, the river was called «Seyhun» ( ,)نوحيسnamed one of the four rivers in paradise. The name of the Syr Darya from the Persian language has been used since ancient times. In Western countries, until the 20th century, this river was called Yaksart. The northern border conquered by Yeskendir Zulkarnay passed through the Syr Darya River. According to Greek historians, Iskander founded the city of Alexandria Eskhata («the most remote Alexandria») in 329 BC. This city is now called Khujand. In 1740-1741, the expedition of D.V. Gladyshev and I. Muravin made a significant contribution to the study of the geography of Kazakh lands.