Polish Armed Forces Command was aware of the might of their foe. Thus their strategy was to bear the initial attack and hold out until the promised offensive by the Western Allies, Great Britain and France. Although on September 3 the Western Allies declared war on Germany, Poland remained not only alone in battle, but in fact from September 17 she was confronted with a second aggressor. Even with Germany’s incredible military superiority, especially in terms of armor and air force, Polish forces attempted to defend the borders. Quickly however they were forced to retreat (there were exceptions, the Polish forces as Westerplatte held out for a week). They retreated into the country, so to organize their defense. On September 8, the battle for Warsaw began.
Polish armies attempted to attack, launching the Battle of the Bzura, one of the largest of WWII. Although the enemy was inflicted considerable losses, the battle ended in defeat. Defensive fighting would have certainly lasted longer, if not for the invasion of the Red Army on September 17. This move also hastened the evacuation of Polish civilian and military command to Romania, where they were interned. On September 27 a besieged Warsaw capitulated. On October 2, units on the Hel peninsula surrendered, and on October 5 so too did Gen. Kleeberg’s soldiers fighting by Kock, Poland. Major Henryk “Hubala” Dobrzanski’s units continued sporadic fighting until Spring 1940. Already in the Fall of 1939, immediately after the end of September Campaign, initial steps were undertaken to begin the formation of an armed conspiracy (See: Underground Army), and in France, the Polish government in exile (See: In Exile) began forming an army.
The Polish War of Defense forced Hitler to postpone his planned aggression against France from Fall 1939 by half a year. When it began, Paris defended itself little longer than Warsaw and, as was written in the Polish underground Informational Bulletin “It is only in light of the battles in the West that the three week long defense of Warsaw, Battle of the Bzura, Westerplatte, shine fully.”