Issues from former occupying forces

From the late 1700s until the end of World War I, Poland did not exist as a country. It was partitioned among the Russian, German (Prussian) and Austrian Empires.
World War I broke out in August 1914 with the Central Powers, Austria and Germany/Prussia on one side and Russia with its western allies on the other side. There was no formal Polish state. Three occupying powers were at war on territory inhabited by the Poles. After the October Revolution in 1917, Russia plunged into civil war and could no longer oversee Polish affairs. In October 1918, the Austrian empire collapsed and in November 1918, the German army withdrew from Warsaw. On 11 November 1918, Poland recovered its independence under the command of marshal Józef Piłsudski.
Long after the recovery of independence of the Republic of Poland, remaining postage issues from former occupying forces were still in circulation. The new Poland did not have a defined territory yet. At first, Poland consisted of the German and Austrian occupied zones. The precise borders were defined during the following three years.

Former Russian sector of partitioned Polish territory after German occupation
In the former Russian sector, between 11 and 17 November 1918, only German stamps were used. From 16 November, the Polish Fischer 2-5 issues were also used.

Former Russian sector of partitioned Polish territory after Austro-Hungarian occupation
On former Austro-Hungarian occupied territory, the Lublin issues (Fischer 17-19 and Fischer 20-29) were used. Also, Austro-Hungarian fieldpost newspaper stamps (Michel 49-52), Bosnia-Hercegovina's express stamps (Michel 117-118) and postage dues (Michel 16, 18-21 and 1-12) were in circulation.

Michel 49

Michel 50

Michel 51

Michel 52

Michel 117

Michel 118

Michel 16

Michel 18

Michel 19

Michel 20

Michel 21

Michel 1

Michel 2

Michel 3

Michel 4

Michel 5

Michel 6

Michel 7

Michel 8

Michel 9

Michel 10

Michel 11

Michel 12

Former Austrian occupied teritory and Silesian Cieszyń
On former Austrian territory (Małopolska - Little Poland) and in Cieszyń, Austrian stamps were used. Although these issues were officially withdrawn from circulation on 20 January 1919, these stamps were still used until the very end of 1919. Beside the Kraków issues (Fischer 30-49), Austrian express stamps (Michel 217-220) and postage dues (Michel 144 and 62) were used. Regardless of their original purpose, these stamps were used as postage stamps and postage dues.

Michel 217

Michel 218

Michel 219

Michel 220

Michel 144

Michel 62

Former Prussian occupied territory
On former Prussian occupied territory, the forerunners of Polish postage stamps were used in combination with German "Germania" issues (Michel 98, 84-88, 101, 103, 90-91, 150) and Michel 94, 107-109 until March 1920 (1 German Mark was equal to 1 Polish Marka). In bylaws, the German stamps had postal validity until March 1920. From October 1919, it was prohibited to sell German stamps at post offices, but the stamps were still used for outpayment of domestic money orders. From April 1920, the German stamps had lost their validity. After that period, parcels stamped with German stamps were regarded unstamped. These parcels were submitted to postage due and the stamps were cancelled with a pen.

Michel 98

Michel 84

Michel 85

Michel 86

Michel 101

Michel 87

Michel 88

Michel 103

Michel 90

Michel 91

Michel 150

Michel 94

Michel 107

Michel 108

Michel 109

Glossary

Prussia is Slavic Eastern Baltic territory, today divided by Poland and Russia. In the 13th century it was conquered by the Teutonic Knights and in 1525 it was acquired by the Hohenzollerns who merged the area with their own German territory to form Brandenburg-Prussia, later shortened to Prussia.
The Austro-Hungarian empire was a large area, including most of central Europe, ruled by the Habsburgs. The Austro-Hungarian empire was enlarged to include the Polish province of Galicia during the partitions.

Resources

Andre Mongeon's stamps of Poland and Polish related areas (home.golden.net)
Partitions of Poland
Russian empire
Prussia
Austria
Austro-Hungarian empire
World War I
October Revolution
Józef Piłsudski