Cieszyn Silesia - historical land Polish and Czech located in the south-eastern part Silesia, covering the area around the city Cieszyn and the Olza River, it is approx. 2,280 km², inhabited by over 800,000 people (463,000 on the Czech side and approx. 350,000 on the Polish side). The boundaries of the region were formed with the establishment of the Cieszyn castellany, mentioned for the first time in 1155, then the region became established as Of the Duchy of Cieszyn, which, from the 15th century onwards, began to lose territorial unity, periodically or permanently, despite this, a sense of bond persisted among the inhabitants for a long time, which undoubtedly results from the centuries-old stable administrative border, regardless of belonging to Austria or Czech. Only after World War I, these areas were divided into two parts: Polish and Czechoslovak (today Czech).
Part of the literature treats Cieszyn Silesia and Upper Silesia as two separate regions, according to other sources, Cieszyn Silesia is located within the historical and geographical borders of Upper Silesia.
The inhabitants of Cieszyn Silesia are characterized by a very strong sense of regional identity, this applies to both the Polish part of the region and the so-called Zaolzie. One of the characteristic features of this region was the great development of the Polish national movement, as well as religious diversity, mainly characterized by the presence of the followers of Lutheranism and Catholicism. It is the main Lutheran center in Poland, where more than half of the approximately 70,000 Polish Evangelicals of the Augsburg tradition live.