Page "Postage stamps and postal history of Austria" Paragraph 10

On 6 April 1850 the Austro-German Postal Union agreement was concluded between the Austro-Hungarian Empire and Prussia to take effect from 1 July 1850.

The primary purpose of the agreement was to provide a uniform system of postal rates.

By 1 June 1852 all the remaining German states joined the Union.

It subsequently became the model for the creation of the Universal Postal Union in 1874.