The postage stamps of Ireland are issued by the postal operator of the independent Irish state. Ireland was part of the United Kingdom of Great Britain and Ireland when the world's first postage stamps were issued in 1840. These stamps, and all subsequent British issues, were used in Ireland until the new Irish Government assumed power in 1922. Beginning on 17 February 1922, existing British stamps were overprinted with Irish text to provide some definitives until separate Irish issues became available. Following the overprints, a regular series of definitive stamps was produced by the new Department of Posts and Telegraphs, using domestic designs. These definitives were issued on 6 December 1922; the first was a 2d stamp, depicting a map of Ireland (including Northern Ireland, which remained a part of the United Kingdom). Since then new images, and additional values as needed, have produced of nine definitive series of different designs.