“ A German art critic and historian. He was born at Prague, and studied at the university of his native city and at Tübingen. He taught successively at Prague, Bonn, Strassburg, and Leipzig. His historical works include: Geschichte des Revolutionszeitalters (1849) ; Oesterreich, Preussen und Deutschland (1851) ; and Geschichte Oesterreichs seit dem Wiener Frieden (1863-65) . His principal works on art are: Die Baukunst des christlichen Mittelalters (1854) ; Geschichte der bildenden Künste im 19. ”