Although chemical analysis of copper alloys of cultural value indicates a wide variety of nickel contents in the range of less than0.01% up to 5%, nickel contents of object-groups originating from certain areas and times lie within relatively small limits. This finding helps to classify objects of questionable origin. In addition, the nickel content being exclusively caused by admixtures of nickel ores to copper ores indicates the kind of copper mine that was worked during the production time of the appropriate object. Despite those copper alloys that go back to the earliest cultures of the Ancient Near East, which show nickel contents up to 2%, most of the ancient alloys are marked out by relatively low nickel contents rarely exceeding 0.05%. During the Middle Ages and even more during the Renaissance, the nickel contents of copper alloys rise distinctly. Objects of the 15th-17th centuries show a rise of nickel contents from 0.1% up to 0.9% on average. That makes it possible to carry our temporal classification of appropriate objects by using material data.