Ravensberg (räˈvənsbĕrkh) [key], former county, W Germany, now in North Rhine–Westphalia. Bielefeld was a major town in the county. In 1346, Ravensberg came under the control of the counts of Berg. It passed, with Berg, to the dukes of Jülich in 1348 and, with Jülich, to the duchy of Cleves in 1521. In 1614 it was taken by Brandenburg.