Opole (; ; ) is a city located in southern Poland on the Oder River and the historical capital of Upper Silesia. With a population of approximately 127,387 as of the 2021 census, it is the capital of Opole Voivodeship (province) and the seat of Opole County. Its built-up (or metro area) was home to 146,522 inhabitants. It is the smallest city in Poland that is also the largest city in its province. Its history dates to the 8th century, and Opole is one of the oldest cities in Poland. An important stronghold in Poland, it became a capital of a duchy within medieval Poland in 1172, and in 1217 it was granted city rights by Duke Casimir I of Opole, the great-grandson of Polish Duke Bolesław III Wrymouth. During the Medieval Period and the Renaissance, the city was known as a centre of commerce; several main trade routes intersected here, which helped to generate steady profits from transit trade. The rapid development of the town was also caused by the establishment of a seat of regency in Opole in 1816. The first railway connection between Opole, Brzeg and Wrocław was opened in 1843 and the first manufacturing plants were constructed in 1859, which greatly contributed to the city's regional significance. The city's extensive heritage entails several cultures of Central Europe, as it was under periods of Polish, Bohemian (Czech), Prussian, and German rule. Opole formally became part of Poland again in 1945 after the end of World War II. Many German Upper Silesians and Poles of ethnic German ancestry still reside in the Opole region; but, following the 1945–46 expulsions, in the city of the 21st century, ethnic Germans make up less than 3% of the population. There are four higher education establishments in the city: the Opole University, Opole University of Technology, a Medical College and the private Higher College of Management and Administration. The National Festival of Polish Song has been held here annually since 1963. Each year new regular events, fairs, shows and competitions take place. Opole is sometimes referred to as "Polish Venice", because of its picturesque Old Town and several canals and bridges connecting parts of the city. Names and etymology The name Opole likely originated from the medieval Slavic term for a group of settlements. Names for the city in other relevant languages include , , , or . History In Medieval Poland