Bactria

Bactria (/ˈbæktriə/; Bactrian: βαχλο, Bakhlo), or Bactriana, was an ancient Iranian civilization in Central Asia, located in the area south of the Oxus River (modern Amu Darya) and north of the Hindu Kush mountains, within modern-day Afghanistan, Tajikistan and Uzbekistan. Bactria was strategically located south of Sogdia and west of the Pamir Mountains. These mountain ranges acted as "walls" protecting Bactria from three sides, with the Pamir mountains to the north and the Hindu Kush to the south forming a junction, and the Karakoram range towards the east.

Called "beautiful Bactria, crowned with flags" by the Avesta, the region is considered, in the Zoroastrian faith, to be one of the "sixteen perfect Iranian lands" that the supreme deity, Ahura Mazda, had created. It was once a small and independent kingdom struggling to survive against nomadic Turanians. One of the early centres of Zoroastrianism, and capital of the legendary Kayanian dynasty, Bactria is mentioned in the Behistun Inscription of Darius the Great as one of the satrapies of the Achaemenid Empire; it was a special satrapy, ruled by a crown prince or an intended heir. Bactria was the centre of Iranian resistance against the Greek Macedonian invaders after the fall of the Achaemenid Empire in the 4th century BC, but eventually fell to Alexander the Great.

After the death of Alexander, Bactria fell to his general, Seleucus I. The Seleucids lost the region to the satrap Diodotus I, when he declared independence; thus marking the beginning of the Greco-Bactrian and Indo-Greek Kingdoms. By the 2nd century BC, Bactria was conquered by the Parthian Empire, and, in the early 1st century, by the Kushan Empire, believed to have been founded by the Yuezhi. Bactrian (natively known as ariao, 'Iranian'), an Eastern Iranian language, was the common language of Bactria and the surroundings areas, from ancient until early medieval times.

Shapur I, the second Sasanian King of Kings of Iran, conquered western parts of the Kushan Empire in the 3rd century, and the Kushano-Sasanian Kingdom was established. The Sasanians lost Bactria in the 4th century, but reconquered it in the 6th century.

The Islamization of Bactria began with the Muslim conquest of Iran in the 7th century. The capital city of Bactra was the centre of an Iranian Renaissance in the 8th and 9th centuries, and New Persian as an independent literary language first emerged in this region. The Samanid Empire was formed in Eastern Iran by the descendants of Saman Khuda, a Persian from Bactria, leading to the spread of the Persian language in the region, and the decline of Bactrian.