Frederick William IV the eldest son and successor of Frederick William III of Prussia, reigned as King of Prussia from 1840 to 1861. Also referred to as the "romanticist on the throne", he is best remembered for the many buildings he had constructed in Berlin and Potsdam, as well as for the completion of the Gothic Cologne Cathedral. In politics, he was a conservative, and in 1849 rejected the title of Emperor of the Germans offered by the Frankfurt Parliament as not the Parliament's to give.