Complex sentence: In 1832, the "Rheinkreis" became the focal point of then current liberal movements when a big gathering, the Hambach Festival, took place near Neustadt an der Weinstraße, an event which is considered a milestone in German history.
Split into simpler sentences: In 1832, the "Rheinkreis" became the focal point of liberal movements. The Hambach Festival, a large gathering near Neustadt an der Weinstraße, proved fertile ground for what came to be considered a milestone in German history.