Witold Pilecki (13 May 1901 – 25 May 1948; Polish pronunciation: [ˈvitɔlt piˈlɛt͡skʲi]; codenames Roman Jezierski, Tomasz Serafiński, Druh, Witold) was a Polish soldier, a rittmeister of the Polish Cavalry during the Second Polish Republic, the founder of the Secret Polish Army (Tajna Armia Polska) resistance group in German-occupied Poland in November 1939, and a member of the underground Home Army (Armia Krajowa), which was formed in February 1942.