Since there are no generally applicable methods for dating metal objects, their age must be deduced from their composition. Using the analysis of German Renaissance objects made of copper alloys as an example, it is demonstrated that in the course of three centuries six elements -- tin, lead, iron, nickel, antimony, and arsenic -- change in such a characteristic way in the course of time that a precise determination of the time of manufacture from the composition of the alloy is possible. -- AATA