Władysław Bortnowski was a Polish historian, military commander and one of the highest ranking generals of the Polish Army. He is most famous for commanding the Pomorze Army in the Battle of the Bzura during the invasion of Poland in 1939. He is also notable for serving as president of the Józef Piłsudski Institute of America between 1961 and 1962.

The Battle of the Bzura was both the largest battle and Polish counter-attack of the German invasion of Poland and was fought from 9 to 19 September. The battle took place west of Warsaw, near the Bzura River. It began as a Polish counter-offensive, which gained initial success, but the Germans outflanked the Polish forces with a concentrated counter-attack. That weakened Polish forces and the Poznań and Pomorze Armies were destroyed. Western Poland was now under German occupation. The battle has been described as "the bloodiest and most bitter battle of the entire Polish campaign". Winston Churchill called the battle an "ever-glorious struggle".