Complex sentence: They centered on the disputed areas of Cieszyn Silesia, Orava Territory and Spiš, and after World War II broadened to include areas around cities Klodzko and Racibórz, which until 1945 had belonged to Germany.
Split into simpler sentences: They centered on the disputed areas of Cieszyn Silesia, Orava Territory and Spiš. After World War II they broadened to include areas around the cities of Klodzko and Racibórz, which until 1945 had belonged to Germany.