declining health of his father. In July 1925 Pilecki was assigned to the 26th Lancer Regiment with the rank of Chorąży (ensign). Pilecki would be promoted to podporucznik (second lieutenant, with seniority from 1923) the following year. Also in 1926, in September, Pilecki became the owner of his family's ancestral estate, Sukurcze, in the Lida District of the Nowogródek Voivodeship. In 1931, he married . They had two children, born in Wilno over the next two years: Andrzej and . Pilecki actively supported the local farming community. He was also an amateur poet and painter. He organized the Krakus Military Horsemen Training program in 1932 and was appointed to command the 1st Lida Military Training Squadron, which in 1937 was placed under the Polish 19th Infantry Division. In 1938, Pilecki received the Silver Cross of Merit for his activities. World War II Polish September Campaign With Polish-German tensions growing in mid-1939, Pilecki was mobilized as a cavalry platoon commander on 26 August 1939. He was assigned to the 19th Infantry Division under Major General Józef Kwaciszewski, part of the Army Prusy and his unit took part in heavy fighting against the advancing Germans during the invasion of Poland. The 19th Division was almost completely destroyed following a clash with the German forces on the night of 5/6 September at the battle of Piotrków Trybunalski. Its remains were incorporated into the 41st Infantry Division, which was withdrawn to the southeast toward Lwów (now Lviv, Ukraine) and the Romanian bridgehead. In the 41st Division, Pilecki served as divisional second-in-command of its cavalry detachment, under Major Jan Włodarkiewicz. He and his men destroyed seven German tanks, shot down one aircraft, and destroyed two more on the ground. On 17 September, the Soviet Union invaded eastern Poland, which worsened the already desperate situation of the Polish forces. On 22 September, the 41st Division suffered a major defeat and capitulated. Włodarkiewicz and Pilecki were among the many soldiers who did not follow the order of Commander-in-Chief General Edward Śmigły-Rydz to retreat through Romania to France, instead opting to stay underground in Poland. Resistance On 9 November 1939 in Warsaw, Major Włodarkiewicz, Second Lieutenant Pilecki, Second Lieutenant Jerzy Maringe, Jerzy Skoczyński, and brothers Jan and Stanisław Dangel founded the Secret Polish Army (, TAP), one of the first underground organizations in Poland. Włodarkiewicz became its leader, while Pilecki became TAP's organizational head as it expanded to