The Principality of Merv was the successor state of Sassanid Persia. Centered around the city of Merv of modern day Uzbekistan, Merv could never levy enough soldiers to defend itself, therefore it often appealed to neighbouring empires for protection. First it was a protectorate of the Khazars until it defected to the Ummayad Caliphate in 669. The Khazars were able to devastate the area whilst the Arabs backs were turned, though they never formed in enough strength to capture Merv. That distinction was left for later, when in 1054, the Seljuk Turks invaded Ummayad territory, crushing their armies in Uzbekistan. On their way through, the Seljuks stopped off by Merv, and, in wonder at its ancient beauty, took the city almost bloodlessly, making it the capital of the Sultanate of Great Seljuk. As a result, though to no ones great consternation, the Principality of Merv ceased to exist.