and the 2/6 of 1899 was reprinted with a new watermark in 1919. That year, a 10/- value with a modified version of the 1899 St Paul's Shipwreck design was released. 1530 copies were issued, and today it is Malta's most expensive stamp. Two war tax stamps with denominations of ½d and 3d were issued in 1917 and 1918, during World War I. In late 1921 and early 1922, some of the 1914–1919 issues were reprinted with a new watermark (including the 10/- value, but this is not as scarce as the 1919 issue). The 2d value of this issue had a new design. On 15 April 1922, this stamp was also issued locally surcharged after there was a shortage of ¼d stamps. In 1921, Malta was granted a limited form of self-government which led to the establishment of a Senate and Legislative Assembly. To commemorate this, 1899–1922 definitive stamps were locally overprinted and were issued between 12 January and 29 April 1922. Between August 1922 and 1926, a set of stamps known as the Melita issue was released, with face values between ¼d and £1. The stamps featured allegorical representations and they were designed by the Maltese artists Edward Caruana Dingli and Gianni Vella. In 1926, separate revenue stamps began to be issued again, so the Melita stamps up to 10/- were issued with a overprint. Two sheets of the 3d value were discovered with the overprint inverted, and uncertainty about the error's issue led to a political scandal in 1930. A series of postage stamps inscribed was issued between 1926 and 1927. They were printed by Waterlow and Sons instead of De La Rue (which had printed all of Malta's stamps since 1860). The values of ¼d to 6d depict George V and the coat of arms of Malta, while the values of 1/- to 10/- have engraved designs. Air mail was introduced on 1 April 1928, and the 6d stamp was issued overprinted as Malta's first airmail stamp. In 1928, it was decided that dual-purpose postage and revenue stamps would be issued again instead of having separate issues. The 1926–1927 stamps were issued with overprints in 1928, and a series of stamps with amended inscriptions was issued in 1930. King George VI and Queen Elizabeth II definitives (1938–1964) In 1938, a definitive set of stamps with denominations between ¼d and 10/- depicting the new monarch George VI