The writer František Křelina (1903-1976) graduated from the teaching institute in Jičin. He first taught at village elementary schools in the Nova Paka and Turnov regions. From the mid-1930s, he was a special subject teacher at the council school in Česky Dub. After the town was occupied following the Munich agreement in 1938, he worked at schools in Prague, where his family had also moved. He considered his teaching profession to be a mission. His success and his popularity are evidenced by the extant correspondence with his former students until the end of his life. His teaching activities were terminated by force in 1951, when he was arrested and subsequently, in 1952, sentenced in a political process to 12 years in prison. He was released on amnesty in 1960, but he was not allowed to return to his profession. He thus worked as a construction labourer, retiring in 1964. In 1965, he was given an unexpected opportunity to work as a substitute teacher at his former school in Česky Dub. Since his rehabilitation proceedings had not been completed, however, he had to leave the school again three days later. In order not to cause problems for the headmaster, he excused his leaving by a pretended illness. Nevertheless, the three days were enough for his personality to leave a deep and lasting impression on the hearts of both his students and his teacher colleagues - their correspondence is full of respect and admiration. The history of the teaching activities of František Křelina, who was not allowed to achieve his full fulfilment, hence demonstrates the violence, malevolence and crimes of Communist totalitarian power.