Rick Miller writes on the Linn's website, "The basis of an omnibus issue is that it is planned and that there is an overseeing authority: Portugal in 1898, Crown Agents in 1935. For Europa issues, the authorities are the joint postal conferences of the European national postal administrations."
This year the centennial of Scouting is being marked with special stamps and souvenir sheets
throughout the world.
Shown above, a Timorese Vasco da Gama stamp from the world's first omnibus issue produced for Portugal and its colonies.
To learn more about omnibus issues, click here.