Merv

Merv, also known as the Merve Oasis, was a major Iranian city in Central Asia, on the historical Silk Road, near today's Mary, Turkmenistan. Human settlements on the site of Merv existed from the 3rd millennium BC until the 18th century AD. It changed hands repeatedly throughout history. Under the Achaemenid Empire, it was the center of the satrapy of Margiana. It was subsequently ruled by Hellenistic Kings, Parthians, Sasanians, Arabs, Ghaznavids, Seljuqs, Khwarazmians and Timurids, among others.

Merv was the capital city of several polities throughout its history. In the beginning of the 9th century, Merv was the seat of the caliph al-Ma'mun and the capital of the entire Islamic caliphate. It served later as the seat of the Tahirid governors of Khorasan.