According to Diane Wirth, as a rule brass deteriorates with time, but perhaps can be preserved because of the combination of copper, zinc, and possibly others metals. Bronze, which also has a copper base, has been found in the form of inscribed tablets from many ancient sites. One in particular has been dated to the sixth century B.C.; the same time the Book of Mormon states the plates of Laban existed. This bronze plaque was discovered in 1860 near Styria, Greece, and contained laws for the distribution of land. It is now housed at the National Archaeological Museum in Athens. [Diane E. Wirth, A Challenge to the Critics, p. 42]