More than 50 bronze sculptures from the 16th century of the Residenz at Munich are exposed to weathering and accelerated by the action of air polluting gases. The metal from 32 sculptures was analyzed and it was found that bronzes rich in lead were the most extensively corroded. Various compounds of the patina were identified with x-ray diffraction techniques. The corrosion phenomena were studied with the metallographic microscope. Methods for cleaning and preservation are proposed.