Birjand is the east Iranian provincial capital of South Khorasan and the centre of the county Birjand resp. Quhestan, known for its saffron, barberry, rug and handmade carpet exports.The city of Birjand had a population of 187,020 people at the time of the last official census in 2013.Being close to the Afghanistan border, Birjand is located on the "Silk Road" of opium smuggled from Afghanistan on the way to Europe (also dubbed the "opium crescent").The city has a dry climate with significant difference between day and night temperatures. It is a fast-growing city, thus becoming one of the major centres in the East of Iran.HistoryThe first citation of the city in the historical literature belongs to the famous book Mojem Alboldan, by Yaqut Homavi (13th century) which introduces the Birjand as the most beautiful town in the Qohestan. Before this, Birjand had been probably not as big and important as a municipality but rather as a rural community. However, the Birjand geographical area had its historical and political importance long before the emergence of the city of Birjand. Many citations of the region are available in the original literature like Ehya -ol- Molook of the once important localities in the area. Apart from literature, the oldest evidence on the history of the region is the ancient Lakh-Mazar inscription in the Kooch village some 25km south east of Birjand. Numerous fine drawings and inscriptions are carved on an igneous rock surface. The inscriptions include pictograms as well as Arsacid Pahlavi, Sasanian Pahlavi, Arabic and Persian scripts. The former tribe famous for the region of Birjand is called Sagarthian - historically in union with the Parthian.