Giesebrecht, Wilhelm von (vĭlˈhĕlm fən gēˈzəbrĕkht) [key], 1814–89, German historian. A gifted student of Ranke, he later taught at the Univ. of Königsberg. His Geschichte der deutschen Kaiserzeit [history of the imperial period of Germany] (5 vol., 1855–88) remains a monument of scholarship as well as literature. It terminates with the reign of Emperor Frederick I.