Complex sentence: The Unionskirche (Union Church) is the Protestant parish church of Idstein, a major town in the German Rheingau-Taunus-Kreis, which was a residence of the Counts of Nassau.
Split into simpler sentences: The Unionskirche (Union Church) is the Protestant parish church of Idstein, a major town in the German Rheingau-Taunus-Kreis. Idstein was a residence of the Counts of Nassau.