Method and apparatus for applying unique composite indicia or markings to a succession of articles, in which each unique composite indicium comprises two or more indicia. At least part of each of the indicia may be co-located at a predetermined location on the article with such co-location being unique or distinct for each composite indicium for each article. The indicium may be overprinted with one or more images, logos or color-schemes. A code (e.g. an alphanumeric string) that is stored in a database may be derived from the composite indicium from one or more mathematical properties. The code may be later accessed for identifying or verifying the article with the indicium.