times (7th–6th century BCE), the parts of modern Tajikistan including territories as far as Zeravshan valley in Sogdiana formed parts of ancient Kamboja and the Parama Kamboja kingdoms when it was ruled by the Kambojas till it became part of Persian Achaemenid Empire. After the Persian Empire was defeated by Alexander the Great, the region became the northern part of Hellenistic Greco-Bactrian Kingdom.
From the last quarter of 4th century BCE until the first quarter of the 2nd century BCE, it was part of the Bactrian Empire, from whom it was passed on to Scythian Tukharas and hence became part of Tukharistan. Contact with the Chinese Han Dynasty was made in the 2nd century BCE, when envoys were sent to the area of Bactria to explore regions west of China.
Arabs brought Islam in the 7th century CE. The Samanid Empire supplanted the Arabs and enlarged the cities of Samarkand and Bukhara, which became the cultural centers of Tajiks (both of which are now in Uzbekistan). The Mongols would later take partial control of Central Asia, and later the land that today comprises Tajikistan became a part of the Emirate of Bukhara. A small community of Jews, displaced from the Middle East after the Babylonian captivity, migrated to the region and settled there after 600 BCE, though the majority of the recent Jewish population did not migrate to Tajikistan until the 20th century.
Russian presence
In the 19th century, the Russian Empire began to spread into Central Asia during the Great Game. Between 1864 and 1885 it gradually took control of the entire territory of Russian Turkestan from today's border with Kazakhstan in the north to the Caspian Sea in the west and the border with Afghanistan in the south. Tajikistan was eventually carved out of this territory, which historically had a large Tajik population.
After the overthrow of Imperial Russia in 1917, guerrillas throughout Central Asia, known as basmachi, waged a war against
