Patinae on Cu-base alloys have been characterized by means of GDOS, SEM, XRD and AFM. The effect of a protective coating was tested in aggressive artificial solutions. Patinae and the bulk of several metal Punic objects were also examined. The GDOS results combined with SEM capabilities allow exhaustive investigation of composition, element distribution and microstructure of modified surface in modern bronzes exposed to accelerated ageing tests as well as in ancient bronzes. The SEM data of the patina thickness agree with the GDOS data. The XRD and SEM investigations allow an exhaustive characterization of corrosion products. Corrosion growth in its early stages determines the effectiveness of the patina's protective role and the AFM is a promising technique for investigating this.