These were the major stamp productions for everyday use. Commemorative stamps first appeared in 1929, and these now appear several times a year, celebrating many aspects of Irish life, such as notable events and anniversaries, Irish life and culture, and many famous Irish people. Some definitive and commemorative stamps have been produced in miniature sheet, booklet and coil configurations in addition to the common sheet layout. Postage dues and airmails complete the stamp issues of the two, sequential, Irish stamp-issuing authorities. Two styles of watermark were used though the overprinted issues came with the watermarks of the British stamps provided for overprinting by the British Post Office.