Borujerd (Borūjerd boɾuːˈdʒeɾd) is a city and the capital of Borujerd County, Lorestan Province in western Iran. At the 2016 census, its population was 234,997 people. Among the existing modern cities in Iran, Borujerd is one of the oldest reported at least since the 9th century. In Sassanid Empire, Borujerd was a small town and region neighboring Nahavand. Gaining more attention during Great Seljuq Empire in the 9th and 10th centuries, Borujerd stood as an industrial, commercial and strategic city in Zagros Mountains until the 20th century. In its golden ages, Borujerd was selected as the state capital of Lorestan and Khuzestan region during Qajar dynasty in the 18th and 19th centuries. Due to the existence of a large number of production and industrial units and the supply of their products in the domestic and foreign markets, Borujerd is considered the industrial hub of Lorestan province. The history of Borujerd before the advent of Islam is not well known. Parthian-era artifacts have been discovered in its environs by non-professional excavators. Moreover, one of Iran's oldest mosques, the Jameh Mosque of Borujerd, was constructed on the remains of a Zoroastrian fire temple. This proves that the region was populated before Islam arrived. The Parthian king Orodes II (57-37) is credited by some academics with laying the city's foundation. They believe that "Borujerd" stems from the Middle Persian word Wurūgird/Wulūgird/Orodhkard, meaning "built by Orodes." Others consider it to have been built by the Sasanian king Peroz I (459-484), arguing that "Piruzgird" was its original name, before being changed into "Burugird", and then later Arabicised into "Burujird". The local name of the city is voroogerd. Only from the 9th-century does the name "Borujerd" appear in Islamic chronicles. It first appears in the Kitāb al-buldān of Ibn al-Faqih (903), and is later reported in various forms, such as "Warukird", "Warugird", "Barugird" and "Barujird".