Ploieşti is the county seat of Prahova County and lies in the historical region of Wallachia, Romania. The city is located 56 km (35 mi) north of Bucharest. In 2002, it had a population of 232,527, making it the ninth-largest city in Romania. The town was established in 1596, during the reign of Mihai Viteazul (Michael the Brave). It rapidly flourished as a center for trade and handicraft manufacturing in the 17th and 18th centuries. In the mid-19th century, the Ploieşti region was one of the world's leading oil extraction and refinery sites.