Prague Castle (Hradčany) with Inverted Overprint 'POŠTA ČESKOSLOVENSKÁ 1919'

Czechoslovakia · 1919 · 4k

This stamp features the iconic Prague Castle (Hradčany) design, originally an Austrian issue. It was overprinted 'POŠTA ČESKOSLOVENSKÁ 1919' for use in the newly formed nation of Czechoslovakia. This particular example is a famous error where the overprint was applied upside down, creating a highly sought-after rarity.

Issued shortly after Czechoslovakia's independence in 1918, this overprinted stamp represents the transition from the Austro-Hungarian Empire to a new sovereign state, adapting existing materials for postal use.