Cieszyn Silesia changed from an agricultural to an industrial area on the turn of the 19th century. This happened on account of rapid development and expansion of the Ostrawa-Karwina Coal Basin. A great number of workers and professionals arrived to a rather small territory. They were of Polish, Czech and German origin, with a majority of the Polish, who formed 60.6% of the population. The coal mining region thus became a typical multilingual society. Polish intelligentsia soon started to express the need of founding a secondary school, which would prepare future Polish speaking mining and metallurgical engineers.
On December 8, 1908 the meeting of „Macierz Szkolna“ (Polish educational society) made a decision to establish a private secondary school, expecting it would become government-funded in the near future.
On September 7, 1909 the decree of the new school opening was issued by Austrian Ministry of Education and Religion in Vienna. The inauguration took place on September 23, 1909. The school accepted the name of Juliusz Słowacki, a great Polish romantic poet, whose 100th birth anniversary fell in that particular year. The school has been successful and popular among students since the beginning and undoubtedly reached a very high level of education soon.
During the World War I the school was closed for about 2 months due to teachers´ draft. By November 1914 only two teachers were available for work. A lot of students enlisted in newly formed Polish armed forces voluntarily. There appeared some casualties, too, in the front lines in Italy or Russia. The first graduating exams took place in July 1917.