Started in 1015, only the crypt, the circular towers accompanying the choir, the basements of the western towers and the lower parts of the transept including both apses have retained their original Romanesque forms, while most of the cathedral has been rebuilt in a Gothic style. The remarkable 13th-century glass paintings were lost but have been replaced by new ones in the mid-20th century, created by Charles Crodel who tried to uphold the medieval imagery. The Romanesque crucifix and a 12th-century baptismal font made from red sandstone still exist. In the southern enclosure, remarkable pieces from the cathedral treasure are presented, including valuable manuscripts like an illustrated 13th-century Bible, a Romanesque portable altar, a 13th-century ivory casket and reredos as well as the mummified hand of 11th-century anti-king Rudolf of Swabia. A facsimile of the famous pagan Merseburg Incantations is exhibited in the "charms vault". Moreover the cathedral includes a romantic tuned, 1850s grand organ by Friedrich Ladegast.