History of the Prophets and Kings
In 729, the new Arab governor, Ashras ibn Abdallah al-Sulami, managed to cross the Oxus River and reach Bukhara against stiff opposition by the Türgesh and their Soghdian allies. The Arab victory was narrow, and the Türgesh were able to withdraw unmolested back towards the region of Samarkand, which brought them near the Arab fortress of Kamarja, a fortified town some seven "farsakhs"—roughly —west of Samarkand. The subsequent siege of Kamarja, narrated in al-Tabari's "History of the Prophets and Kings" is, in the words of the historian Hugh N. Kennedy, "one of the most vividly described set pieces of the war".