Leaders of Polish mathematics between the two world wars

In the period 1918-1939 mathematics in Poland was led by a few people aiming at clearly defined but somewhat different goals. They were: S. Zaremba in Cracow, W. Sierpiński and S. Mazurkiewicz in Warsaw, and H. Steinhaus and S. Banach in Lvov. All were chairmen and editors of mathematical journals, and each promoted several students to continue their efforts. They were highly successful both locally and internationally.