Historically, the region of Silesia (Lower and Upper) has been inhabited by Polish (West Slavic Lechitic people), Czechs, and by Germans.

The names of Silesia in different languages most likely share their etymology—Polish: Śląskⓘ; German: Schlesien pronounced [ˈʃleːzi̯ən] ⓘ; Czech: Slezsko [ˈslɛsko]; Lower Silesian: Schläsing; Silesian: Ślōnsk [ɕlonsk]; Lower Sorbian: Šlazyńska [ˈʃlazɨnʲska]; Upper Sorbian: Šleska [ˈʃlɛska]; Latin, Spanish and English: Silesia; French: Silésie; Dutch: Silezië; Italian: Slesia; Slovak: Sliezsko; Kashubian: Sląsk.

[7] According to some Polonists, the name Ślęża [ˈɕlɛ̃ʐa] or Ślęż [ɕlɛ̃ʂ] is directly related to the Old Polish words ślęg [ɕlɛŋk] or śląg [ɕlɔŋk], which means dampness, moisture, or humidity.

[9] The term "Silesia" is a Latinized word of the original Polish/Lechitic name "Śląsk" inhabited by the ancient Lechitic tribes called Ślężanie.

During the German occupation of Poland, Nazi authorities conducted a census in East Upper Silesia in 1940.

[12] After World War II in Poland, the 1945 census showed a sizable group of people in Upper Silesia who declared Silesian nationality.

[13] Archaeological findings of the 20th century in Silesia confirm the existence of an early settlement inhabited by Celtic tribes.

The Slavs, predominantly White Croats entered the depopulated territory of Silesia in the first half of the 6th century.

Local West Slavs began to erect a series of defensive systems, such as the Silesian Przesieka and the Silesia Walls to guard them from invaders.

[17] The 9th-century Bavarian Geographer records the tribal names of the Opolanie, Dadosesani, Golenzizi, Lupiglaa, and the Ślężanie.

Later, in 990, the first Polish state was created by Duke Mieszko I, and then expanded by king Boleslaw I at the beginning of the 11th century.

Silesia was part of Great Moravia, then Kingdom of Bohemia and finally the Piast monarchy of Poland.

Beginning in the 13th century, Slavic Silesia began to be settled by Germans from various parts of Germany, including Prussia and Austria.

In the Middle Ages, various German dialects of the new settlers became widely used throughout Lower Silesia and some Upper Silesian cities.

[26][27] In 1742, most of Silesia was seized in the War of the Austrian Succession by King Frederick the Great of Prussia, who named himself a 'Piast prince' (he was actually a remote descendant) in his first declaration.

The cultural distance of Upper Silesians from the German population resulted in the development of Polish national awareness at the turn of the nineteenth and twentieth centuries, culminating in the pro-Polish movements at the end of World War I.

[31] Between 1955 and 1959, under the supervision of the Red Cross, some of the remaining Silesians were able to emigrate to West and East Germany to reunite with their families there.

Since the end of Communist rule in Poland, there have been calls for greater political representation for the Silesian ethnic minority.

In year 1819, the Breslau Regency had 833,253 inhabitants, the majority of whom—755,553 (90%)—were German-speakers; with a Polish-speaking minority numbering 66,500 (8%); as well as 3,900 Czechs (1%) and 7,300 Jews (1%).

The earliest exact census figures on ethnolinguistic or national structure (Nationalverschiedenheit) of the Prussian part of Upper Silesia, come from year 1819.

show that large demographic changes took place between 1819 and 1910, with the region's total population quadrupling, the percent of German-speakers increasing significantly, and that of Polish-speakers declining considerably.

[42] Polish authors before 1918 estimated the number of Poles in Prussian Upper Silesia as slightly higher than according to official German censuses.

[48] In total, over seven hundred towns and villages voted in favour of Poland, especially in the counties of Pszczyna,[49] Rybnik,[50] Tarnowskie Góry,[51] Toszek-Gliwice,[52] Strzelce Opolskie,[53] Bytom,[54] Katowice,[55] Lubliniec,[56] Zabrze,[57] Racibórz,[58] Olesno,[59] Koźle[60] and Opole.