The small city of Bonn served as the residence of the “emigrated” archbishops and electors of Cologne from 1238 until the conquest of Cologne and Bonn by French revolutionary troops in 1794. The period of French rule officially ended with Prussia’s acquisition of territory along the Rhine at the Congress of Vienna in 1815, at which point Bonn became part of the Prussian province of the Rhineland. Although Bonn had been secularized by the French and then incorporated into the largely Protestant state of Prussia within a matter of decades, the archbishopric continued to leave its mark on the townscape, as this image makes clear. This view follows the Rhine downstream toward the late Romanesque cathedral on the right (parts of which date from the eleventh century) and the residential castle to its left (rebuilt in the late seventeenth century). The ferry boat in the foreground transports goods down the river. Lithograph by Droessee & Weidner after a steel engraving by the Swiss artist Johann Jakob Tanner (1807–1862), c. 1827.