' YEZDEJIRD III., the last of the Persian kings, who was defeated by Abdullah, son of the khalif Omar. His lieutenant Rustam opposed the Arabs in an obstinate battle, A.D. 636, at Kadesiah on the Tigris. Rustam was slain, and the leathern apron of the mythical blacksmith Caveh, the ancient standard of the Sassanians, was captured by the Arabs. This victory gave the conquerors the province of Assyria, since called Irak-i-Arabi, and was followed by the sack of Ctesiphon. A second battle at Yalula drove Yezajiid as a fugitive into the hills of Fars ; but 150, 00 Per sians made a final stand at Nehavend, among the hills south of Hamadan, tbe site of tke old Medean capital Ecbatana, and their defeat (A.D. 641) was the final overthrow of the native Persian power, and of the religion of Zoroaster. The standard of the Muhammadans was rapidly carried over the tableland of Iran, and beyond the Oxus.
Isfandiar, brother of Rustam, joined the Arabs, but Yezdejird fled south to Isfahan, then on to Kerman and Balkh, finally taking refuge at Merv. Here he sought the aid of the Khakan of the Turks, and of the emperor of China. The Khakan espoused his cause, and. for seVeral years a desultory
war was waged in the neighbourhood of Merv, but in the end Yezdejird and the Turks retired across the Oxus, about A.II. 31, A.D. 651. Yezde jird perished miserably, A.p. 652, in the hut of a miller, whither he had fled for refuge (Sir W. Muir's Caliphate, pp. 259"- 297). His death occurred in the eighth year of the khalifat of Usnian.
The era of Yezdejird or the Persian era, began on the 16th June A.D. 632. The year con sisted of 365 days only, and therefore its coin mencement, like that of the old Egyptian and , Armenian year, anticipated the Julian year by one day in every four years. This difference amounted to nearly 112 days in the year 1075, when it was reformed by Jalal - ud - Din, who ordered that in future the Persian year should receive an additional day whenever it should appear necessary to postpone the commencement of the following year, that it might occur on the day of the sun's passing tbe same degree of the ecliptic.— Gibbon, i. 299 ; Prinsep's Antiquities by Thomas ; Yule, Cathay, i. 85 ; Muir's Caliphate.