Wilhelm Fraenger was a German art historian.

Fraenger was a specialist in the epoch of the German Peasants' War

German Peasants' War

The German Peasants' War or Great Peasants' Revolt was a widespread popular revolt in the German-speaking areas of Central Europe, 1524–1526. At its height in the spring and summer of 1525, the conflict involved an estimated 300,000 peasants: contemporary estimates put the dead at 100,000...

 and of the mysticism of the Late Middle Ages. He wrote important studies of Jerg Ratgeb

Jerg Ratgeb

Jerg Ratgeb was a German painter and contemporary of Dürer.-Life and works:...

, Matthias Grünewald

Matthias Grünewald

Matthias Grünewald or "Mathis" , "Gothart" or "Neithardt" , , was a German Renaissance painter of religious works, who ignored Renaissance classicism to continue the expressive and intense style of late medieval Central European art into the 16th century.Only ten paintings—several consisting...

 and Hieronymus Bosch. His work on Bosch was very influential in its day and considered Bosch under the aspect of occultism, seeing Bosch as an artist guided by an esoteric mysticism.