Polonia Warsaw, founded on 19 November 1911, is the oldest existing sports club in Warsaw, the capital of Poland, best known for its football and basketball teams. It also has track and field, swimming, chess, mountain biking, and contract bridge sections. Historically it also had sections in ice hockey, fencing, tennis, volleyball, hazena, cycling and boxing.

Tadeusz Jerzy Gebethner was a Polish soldier, insurgent, bookseller, and footballer. From 1914 to 1925 he was an active player and captain of the Polonia Warsaw team; later he worked in his family bookstore and publishing business. Tadeusz Gebethner fought in the Polish–Soviet War and Polish September Campaign. Becoming an officer of the Home Army after the invasion, from 1942 he sheltered a Jewish family in his home in Warsaw during the German occupation. A participant of the Warsaw Uprising, he was critically wounded and taken prisoner to Stalag-XIA, where he died from the same injuries on 14 October 1944. For his wartime activities, he was recognised as one of the Polish Righteous Among the Nations in 1981.