learned as many as 15 languages — Polish, Latin, Italian, English, Spanish, Portuguese, French, German, Luxembourgish, Dutch, Ukrainian, Serbo-Croatian, Czech, Slovak, and Esperanto, nine of which he used extensively as pope. In 1939, after invading Poland, Nazi Germany's occupation forces closed the university. Able-bodied males were required to work, so from 1940 to 1944 Wojtyła variously worked as a messenger for a restaurant, a manual labourer in a limestone quarry and for the Solvay chemical factory, in order to avoid deportation to Germany. In February 1940, he met Jan Tyranowski who introduced him to the Carmelite spirituality and the "Living Rosary" youth groups. In that same year he had two major accidents, suffering a fractured skull after being struck by a tram and sustaining injuries which left him with one shoulder higher than the other and a permanent stoop after being hit by a lorry in a quarry. His father, a former Austro-Hungarian non-commissioned officer and later officer in the Polish Army, died of a heart attack in 1941, leaving Wojtyła as the immediate family's only surviving member. Reflecting on these times of his life, nearly forty years later he said: "I was not at my mother's death, I was not at my brother's death, I was not at my father's death. At twenty, I had already lost all the people I loved." After his father's death, he started thinking seriously about the priesthood. In October 1942, while World War II continued, he knocked on the door of the Bishop's Palace, Kraków, and asked to study for the priesthood. Soon after, he began courses in the clandestine underground seminary run by the Archbishop of Kraków, Cardinal Adam Stefan Sapieha. On 29 February 1944, Wojtyła was hit by a German truck. German Wehrmacht officers tended to him and sent him to a hospital. He spent two weeks there recovering from a severe concussion and a shoulder injury. It seemed to him that this accident and his survival was a confirmation of his vocation. On 6 August 1944, a day known as "Black Sunday", the Gestapo rounded up young men in Kraków to curtail the uprising there, similar to the recent uprising in Warsaw. Wojtyła escaped by hiding in the basement of his uncle's house at 10 Tyniecka Street, while the German troops searched above. More than eight thousand men and boys were taken that day, while Wojtyła escaped to the Archbishop's