Bielefeld is an independent city that is the largest city of the Ostwestfalen-Lippe Region. The city is situated below a pass separating the Northern and Southern Teutoburg Forest. The centre of Bielefeld is situated on the eastern side of the Teutoburg Forest, but the modern city incorporates boroughs on the opposite side and on the hilltops. Founded in 1214 by Count Hermann IV of Ravensberg to guard a pass crossing the Teutoburg Forest, Bielefeld was the "city of linen" as a minor member of the Hanseatic League. After the Cologne-Minden railway opened in 1849, the Bozi brothers constructed the first large mechanised spinning mill in 1851. The Ravensberg Spinning Mill was built from 1854 to 1857, and metal works began to open in the 1860s.
Bielefeld is home to a significant number of internationally operating companies, including Dr. Oetker, Gildemeister and Schüco. It has a university and several Fachhochschulen. Bielefeld is also famous for the Bethel Institution, and for the Bielefeld Conspiracy, which satirises conspiracy theories by claiming that Bielefeld does not exist. This concept has been used in the town's marketing and alluded to by Chancellor Angela Merkel.