Short biography of Stefan Banach with correcting the entry in the St. Andrews biography by Waclaw Szybalski and Stanislaw Kosiedowski
Born: 30 March 1892 in Kraków, Austria-Hungary (now Poland)
Died: 31 Aug 1945 in Lwów, Soviet-occupied Eastern Poland, that in 1945 was in the process of ethnic cleansing (deportation) of Polish population by the Soviet authorities (now Lviv, Ukraine).
His grave is shown in this picture
Banach's father had never given his son much support, but now once he left school he quite openly told Banach that he was now on his own. Banach left Kraków and went to Lwów where he enrolled in the Faculty of Engineering at Lwów Technical University (Politechnika Lwowska). It is almost certain that Banach, without any financial support, had to support himself by tutoring. This must have occupied quite a lot of his time and when he graduated in 1914 he had taken longer to complete the course than was normal. He had returned to Kraków frequently during the period of his studies in Lwów from 1910 to 1914. It is not entirely clear what Banach's plans were in 1914 but the outbreak of World War I in August, shortly after his graduation, saw Banach leave Lwów.
At the time Banach studied there, Lwów was, a under Austrian control as it had been from the partition of Poland in 1772. In Banach's youth the polish Poland, in some sense, existed only under Austian occupation in Kraków and in Lwów, but did not exist and Russia-controlled much of the country. Warsaw only had a Russian language university and was situated in what was named "Vistula Land". With the outbreak of World War I, the Russian troops occupied the city of Lwów. Banach was not physically fit for army service, having poor vision in his left eye. During the war he worked building roads but also spent time in Kraków where he earned money by teaching in the local schools. He also attended mathematics lectures at the Jagiellonian University in Kraków and, although this is not completely certain, it is believed that he attended Zaremba's lectures.
A chance event occurred in the spring of 1916 which was to have a major impact on Banach's life. Steinhaus, who had been undertaking military service, was about to take up a post at the Jan Kazimierz University in Lwów. However he was living in Kraków in the spring of 1916, waiting to take up the appointment. He would walk through the streets of Kraków in the evenings and, as he related in his memoirs:-
Banach was offered an assistantship to Lomnicki at Another important publishing venture, begun in 1931, was a new series of Mathematical Monographs. These were set up under the editorship of Banach and Steinhaus from Lwów and Knaster (who also fed lice in Lwów in 1941-44; se below) , Kuratowski, Mazurkiewicz, and Sierpinski from Warsaw. The first volume in the series Théorie des Opérations linéaires was written by Banach and appeared in 1932. It was a French version of a volume he originally published in Polish in 1931 and quickly became a classic. In 1936 Banach gave a plenary address at the International Congress of Mathematicians in Oslo. In this address he described the work of the whole of the Lwów school, and he also spoke of the plans which they had to develop their ideas further.
Another important influence on Banach was the fact that Kuratowski was appointed to the Lwów Technical University (Politechnika Lwowska) in 1927 and worked there until 1934. Banach collaborated with Kuratowski and they wrote some joint papers during this period.
The way that Banach worked was unconventional. He liked to do mathematical with his colleagues in the cafés of Lwów. Ulam recalls in  frequent sessions in the Kawiarnia Szkocka (Scottish Café):-
It was difficult to outlast or outdrink Banach during these sessions. We discussed problems proposed right there, often with no solution evident even after several hours of thinking. The next day Banach was likely to appear with several small sheets of paper containing outlines of proofs he had completed.
You can see a picture of the Scottish Café on this page
Andrzej Turowicz, also a professor of mathematics at the an Kazimierz University in Lwów, also described Banach's style of working (see ):- Lwów Technical University (Politechnika Lwowska) in 1920. Lwów was now a part of independent Poland. He lectured there in mathematics and submitted a dissertation for his doctorate under Lomnicki's supervision. This was, of course, not the standard route to a doctorate, for Banach had no university mathematics qualifications. However, in polish Lwów an exception was made to allow him to submit On Operations on Abstract Sets and their Application to Integral Equations. This thesis :-
... is sometimes said to mark the birth of functional analysis.
In 1922 the Jan Kazimierz University in Lwów awarded Banach his habilitation for a thesis on measure theory. The University Calendar for 1921-22 reports :-
In 1939, just before the start of World War II, Banach was elected as President of the Polish Mathematical Society. At the beginning of the war Soviet troops occupied Lwów, and acted as if they have incorporated Lwów (and eastern Poland, which amounted to 51% of pre-WWII Poland) into Soviet Union. Banach had been on good terms with the Soviet mathematicians before the war started, visiting Moscow several times, and he was treated well by the new Soviet administration. He was allowed to continue to hold his chair at the university and he became the Dean of the Faculty of Science at the university, now renamed the Ivan Franko University. Banach's father came to Lwów fleeing from the German armies advancing towards Kraków. Life at this stage was little changed for Banach who continued his research, his textbook writing, lecturing and sessions in the cafés. Sobolev and Aleksandrov visited Banach in Lwów in 1940, while Banach attended conferences in the Soviet Union. He was in Kiev when Germany invaded the Soviet Union and he returned immediately to his family in Lwów.
"The Nazi occupation of Lwów (Lvov, Lemberg, Lviv) that started in June 1941 meant that Banach lived under very difficult conditions since University was closed. He was arrested under suspicion of trafficking in German currency but released after a few weeks. Luckily, he survived a period when Polish academics were murdered, including his doctoral supervisor Lomnicki, dying on the tragic night of 3 July 1941 when massacres of 50 Polish Professors (some with their wifes and sons) occurred. See here
Towards the end of 1941, Banach was among those saved by the Polish Professor Rudolf S. Weigl by feeding lice in Weigl-directed Institute, which operated in Polish Lwów since 1920s, and also during Soviet (1939 - 1941) and then German occupations. See here
Feeding lice in this "Institut fuer Fleckfieber" was to be his life during the remainder of the Nazi occupation of Lwów up to July 1944. "
As soon as the Soviet troops retook Lwów Banach renewed his contacts. He met Sobolev outside Moscow but clearly he was by this time seriously ill. Sobolev, giving an address at a memorial conference for Banach, said of this meeting (see for example ):-
Despite heavy traces of the war years under German occupation, and despite the grave illness that was undercutting his strength, Banach's eyes were still lively. He remained the same sociable, cheerful, and extraordinarily well-meaning and charming Stefan Banach whom I had seen in Lwów before the war. That is how he remains in my memory: with a great sense of humour, an energetic human being, a beautiful soul, and a great talent.
Banach planned to go to Kraków after the war to take up the chair of mathematics at the Jagiellonian University but he died in Lwów in 1945 of lung cancer.