Tajikistan harkens to the Samanid Empire (819–999). The Tajik people came under Russian rule in the 1860s. The Basmachi revolt broke out in the wake of the Russian Revolution of 1917 and was quelled in the early 1920s during the Russian Civil War. In 1924, Tajikistan became an Autonomous Soviet Socialist Republics of the Soviet Union, the Tajik ASSR, within Uzbekistan. In 1929, Tajikistan was made one of the component republics of the Soviet Union – Tajik Soviet Socialist Republic (Tajik SSR) – and it kept that status until gaining independence 1991 after the dissolution of the Soviet Union. It has since experienced three changes in government and the Tajikistani Civil War. A peace agreement among rival factions was signed in 1997. Antiquity (600 BC – 651 AD) Tajikistan was part of Scythia in Classical Antiquity. Sogdiana, Bactria, Merv and Khorezm were the four principal divisions of Ancient Central Asia inhabited by the ancestors of the present-day Tajikistani Tajiks. Tajiks are now found only in historic Bactria and Sogdiana. Merv is inhabited by the Turkoman and Khorezm by Uzbeks and Kazakhs. Sogdiana was made up of the Zeravshan and Kashka-Darya river valleys. Currently, two of the surviving peoples of Sogdiana who speak a dialect of the Sogdian language are the Yaghnobis and Shugnanis. Tajikistan was part of the Bactria-Margiana Archaeological Complex in the Bronze Age, candidate for Proto-Indo-Iranian or Proto-Iranian culture. Bactria was located in northern Afghanistan (present-day Afghan Turkestan) between the mountain range of the Hindu Kush and the Amu Darya (Oxus) River and some areas of current south Tajikistan. During different periods, Bactria was a center of various Kingdoms or Empires, and is probably where Zoroastrianism originated. The "Avesta"—the holy book of Zoroastrianism—was written in the old-Bactrian dialect; it is also thought that Zoroaster was most likely born in Bactria. Some authors have also suggested that in the 7th and 6th century BCE parts of modern Tajikistan, including territories in the Zeravshan valley, formed part of Kambojas, which were referenced in the Mahabharata epic as the Parama Kamboja, before it became part of the Achaemenid Empire.Linguistic evidence, combined with ancient literary and inscriptional evidence suggest the Kambojas originally emigrated from Central Asia. Achaemenid Period (550 BC – 329 BC) During the Achaemenid period, Sogdiana and Bactria were part of the Achaemenid empire. Sogdians and Bactrians occupied important positions in the administration and military of the Achaemenid Empire Hellenistic