The first omnibus has been said to be the issue of 1898 by the Portuguese colonial empire to commemorate the quatercentenary of Vasco de Gama's discovery of the sea route to India.
[3] Many others have followed, usually on themes related to the British Royal Family, but also for subjects such as Freedom from Hunger (1963) and the 1966 Football World Cup.
Not every colony necessarily participates in every issue, although the revenue produced by the stamps is a valuable source of income for many smaller colonies/countries which may have few other ways of raising funds.
A list of British Omnibus issues is given below: 1935 - Silver Jubilee 1937 - Coronation 1945-1946 - Peace and Victory 1948-1949 - Silver Wedding 1949 - Universal Postal Union 1951 - University 1953 - QEII Coronation 1953 - Royal Visit 1958 - West Indies Federation 1963 - Freedom From Hunger 1963 - Red Cross Centenary 1964 - Shakespeare 1965 - International Telecommunication Union 1965 - International Cooperation 1966 - Churchill Memorial 1966 - Football World Cup 1966 - U.N.E.S.C.O Issue 1966 - World Health Organization 1966 - Royal Visit to the Caribbean 1972 - Royal Silver Wedding 1973 - Royal Wedding Princess Anne 1974 - Churchill Centenary 1977 - Royal Silver Jubilee 1978 - 25th Anniversary of Queen Elizabeth's Coronation 1980 - Queen Mothers 80th Birthday 1981 - Charles and Diana Royal Wedding 1982 - Princess Diana 21st and other Birthdays 1985 - Life and Times of Elizabeth the Queen Mother 1990 - Queen Mother's 90th Birthday 1997 - Queen Elizabeth Golden Wedding 1931 - Colonial Exposition 1937 - International Exposition in Paris 1938 - Pierre and Marie Curie 1939 - Rene Caillie 1939 - New York World's Fair 1939 - 150th Anniversary of the Revolution 1942 - Protection of the Infants 1942 - Colonial Education Fund 1944 - Marianne Red Cross 1945 - Felix Eboue 1946 - Victory Anniversary 1946 - Chad to the Rhine 1949 - UPU Anniversary 1950 - Tropical Medicine 1952 - Military Medals 1954 - Liberation Anniversary The omnibus remains popular with countries whose philatelic marketing is handled by the Inter-Governmental Philatelic Corporation as it enables those countries to market their stamps into the lucrative United States and European thematic stamp market by featuring subjects popular in those countries.
While most earlier omnibus issues were genuine attempts to help a group of countries celebrate an anniversary or event, the fact that these became popular with stamp collectors tempted issuing authorities to bring out more stamps than would have otherwise been thought necessary.