In 1745, under the terms of the Treaty of Dresden, Prussia became the new ruler of Silesia. Bolesławiec once again found itself under foreign rule, this time Prussian. Little changed in the lives of the residents, however. The reconstruction of buildings destroyed as early as the 17th century continued. On the ruins of the burned-out castle (which had been destroyed during the Thirty Years’ War), work began in 1752 on rebuilding a church for Protestants. The damaged crafts sector was also rebuilt. As a result, in 1789 the population exceeded 3,000, reaching the level from before the Thirty Years’ War. The town, however, had been completely Germanized, and documents no longer contained surnames of Polish origin.
The beginning of the 19th century once again brought war. In 1813, French troops retreating under pressure from Russian forces blew up Bolesławiec’s defensive walls and city gates.
It was also here that, in October 1813, the commander of the Russian army, M.I. Kutuzov, died. In gratitude, Frederick William III also funded a monument commemorating the great victor over Napoleon. Initially, the obelisk stood in the Market Square; in 1893, it was moved to a square near the defensive walls.
Modern strategy demonstrated the uselessness of massive fortifications, so from 1823 the remaining gates were demolished and the moat and castle pond were filled in. After parts of the defensive walls and grain warehouses had been demolished, a municipal arsenal was built in 1822. In 1857, it was converted into a theatre designed according to the fashions and needs of the time.
In 1845–46, the railway viaduct that still exists today was built. The structure spans both elevated banks of the Bóbr and, thanks to the use of dressed stonework, forms an attractive and light-looking building despite its enormous size. From 1846, Bolesławiec had a regular railway connection with Zgorzelec; a year earlier, it had obtained such a connection with Wrocław. Crafts continued to develop, particularly the production of ceramics. The craftsmen were somewhat conservative, however, and resisted change. They sought to maintain the privilege of limiting the number of workshops to five. They also wanted to preserve the forms traditionally used in the production of vessels. The Prussian government consistently sought to increase the number of workshops, which it achieved in 1759.
Against the will of the guild masters, it also opened the way for newcomers from southern Germany. Despite the government’s efforts, however, once-established forms remained unchanged.
Gradually, Bolesławiec ceramics became known beyond the borders of Silesia. Potters exported their products to the Prussian provinces, Poland and Russia.
In 1871, after the unification of Germany by Prussia, Bolesławiec, together with all of Silesia, found itself within the borders of the German Empire. The French indemnity obtained by Prussia contributed to the expansion of the town and the development of other branches of industry. At the turn of the 19th and 20th centuries, a linen factory, a large worsted-spinning mill, two steam mills and a large water mill were established. Local railway lines were built from Bolesławiec to Nowa Wieś Grodziska in 1906 and to Modła in 1913.
In 1897, the Vocational Ceramic School was opened. It had an enormous impact on enriching forms and mechanizing production. Ceramic products became the town’s main export commodity. Therefore, when Poland introduced new customs rates in 1924, ceramic plants had to drastically limit production and seek new markets. Bolesławiec’s exports began to be directed to Scandinavia. During the Nazi era, the government again sought to raise the level of ceramic production. On Göring’s orders, a cooperative of potters was established to restore the style of former products. In 1936, the ceramic industry ranked first among the other occupations (7 potters, 2 artistic stoneware plants and 4 industrial stoneware plants).
Open-pit mines of so-called faience clay were also operating in the area. During the interwar period, copper ore was extracted nearby (Lena, Lubichów, Konrad I and Konrad II). In total, more than 1.5 million tonnes of copper ore were extracted. It underwent complex concentration processes at the copper smelter in Łąka near Bolesławiec and was only then transported to Hamburg, where pure metal was obtained through electrolysis.
During the Second World War, the town continued to develop. Some ceramic plants manufactured certain aircraft parts.
One of the branches of the Gross-Rosen concentration camp was located in the town. The prisoners worked mainly in copper-ore mines, quarries and open-pit mines.
For more than five centuries, Bolesławiec lay outside the borders of the Polish state (from 1392 to 1945). It was destroyed several times (during the Hussite Wars, the Thirty Years’ War, the Napoleonic Wars, and the First and Second World Wars). Over time, it transformed from a trading and craft town into a fairly well-industrialized, diverse manufacturing town.
Despite the dominance of ceramics, other branches of production also developed. Even in the German state, however, Bolesławiec remained a small town of only approximately 20,000 inhabitants on the periphery of the Third Reich.
On 12 February 1945, the town once again became part of the Polish state.