In the 12th century a settlement was formed there, which name, Olesznica, was derived from alder trees, which grew in the swamps and by the river over the area. It was later renamed Oels, Öls under German influences. In 1255, the Duke of Wrocław Henryk III Biały founded the settlement (a market village or a “pre-founded” town) under the Neumarkter Recht (Polish: Prawo średzkie). As early as 1310, the town had its own coat-of-arms, which was one of the eldest in Silesia.
The town developed due to the formation of the Duchy of Oleśnica, which was taken over by Duke Konrad I Oleśnicki around 1321, who was the founder of the Oleśnica line of the Piast dynasty. The Oleśnica castle, town fortified walls with a moat, as well as churches and a synagogue were all built during the reign of the Piast dynasty.
After the death of the last member of the Piast dynasty, Konrad X Biały Młodszy, the Podiebrad family (descendants of the Czech King Jerzy) became the owners of the Duchy of Oleśnica in 1495 and the period of their administration saw the biggest growth of the town. In 1529, the first Jewish printing house in Silesia was established in the town. In 1538, the Duchy of Oleśnica converted to Protestantism. In the 16th century, the town observed a dynamic advancement in education and the field of music. After the death of the last member of the Podiebrad family in 1647, the Duchy of Oleśnica was taken over by a Silesian line of the Württemberg family, who led to the reconstruction of the town after the damage it suffered during the Thirty Years’ War (1618–1648), as well as to its economic growth and resurgence of cultural traditions and the development of science. The House of Comedy (Polish: Dom Komediowy), which was the first theatre in Oleśnica and one of the first theatres in Silesia, was set up in 1670. Many well-known figures from cultural circles had ties with the ducal court, for example one of the Silesia’s most outstanding poets Johann Scheffler (alias Angelus Silesius).
From 1742, Silesia belonged to Prussia. The further history of Oleśnica, beginning with the year 1792, is associated with the dukes of the Brunswick dynasty. During the reign of the dynasty’s first duke, Friedrich August, an old horse riding school was turned into a theatre, in which professional actors and signers were employed. Friedrich August also took care of economic matters, the renovation of churches, as well as the creation of promenades around the castle and in the town. After his death in 1805, Duke Friedrich Wilhelm started to exercise control over the Duchy. He was killed in 1815 in a battle and became a national German hero.
In 1850, Oleśnica became a garrison town. Barracks, which are preserved to this day, were created at that time. In 1868, the Right Bank Oder Railway was founded and the town began to serve as an important railway junction from that time onwards. The town saw the most remarkable development especially at the turn of the 20th century. Many impressive residential buildings and schools were built in the period from 1896 to 1914. As a result of a growing number of inhabitants, residential construction started to develop after World War I, from 1923 on. A facility which was of cultural importance was Town Halls (Polish: Sale Miejskie) which had a mechanised theatre stage.
The end of World War II with the Soviet Army entering the town was a breakthrough in the town’s history. In the period from January to May 1945, 987 residential buildings (53 % of all the buildings) were destroyed in Oleśnica, with the most damage being done to the buildings at the market square and its vicinity. The most important historical buildings (the castle and the castle church) avoided any damage, while others were reconstructed in the 1960s and 1970s.
After the war, as a result of territorial changes, Silesia along with Warmia, Masuria and Pomerania were incorporated into Poland. It was a new beginning in the Oleśnica’s history. The inhabitants who had lived here until that time were displaced to the territories of today’s German, while from the spring of 1945 on, Poles started to arrive here from different parts of pre-war Poland with the intention of settling in the area. Since 1999, Oleśnica is the county seat in Dolnośląskie Province[[refr:"name"|Based on: M. Nienałtowski, Historia Oleśnicy na 5000 znaków, www.olesnica.org [online] http://www.olesnica.org/Historia%20na%205000%20znakow.htm [accessed: 28 August 2015].]].
- U. M. Bülow von, Oels wie wir es kannten mit Adressenverzeichnis 1935/36, Scheinfeld (1985).
- Führer durch die Stadt Oels und ihre Geschichte, Oels in Schlesien (1927).
- W. Mrozowicz, Oleśnica od czasów najdawniejszych po współczesność, Wrocław (2006).
- M. Nienałtowski, Historia Oleśnicy, www.olesnica.org [online] www.olesnica.org [accessed: 28 August 2015]
- Z. Tempski, Oleśnica – miasto wież i róż, Wrocław (1970).