Complex sentence: The University of Silesia in Katowice has its origins in the Institute of Education in Katowice (Instytut Pedagogiczny w Katowicach), which was founded in 1928; at that time it was the only institution of higher education in the part of Silesia belonging to Poland.
Split into simpler sentences: The University of Silesia in Katowice has its origins in the Institute of Education in Katowice (Instytut Pedagogiczny w Katowicach), which was founded in 1928. At that time it was the only institution of higher education in the part of Silesia belonging to Poland.