Today a center of high tech industry and home to more than half a million people, Dortmund got its start at the end of the first millennium AD and grew as a major stop along the Hellweg trading route. During Prussia's industrialization, Dortmund prospered with the production of coal, steel and beer. The city has a number of historic attractions, including Reinoldikirche (honoring the city's patron saint, Reinoldus) and Marienkirche. South of town are ruins of the 12th-century Hohensyburg Castle.