The year 1392 brought a fundamental change to the lives of the residents of Bolesławiec. Together with the entire duchy, known as Jawor–Świdnica, they came under the rule of the Luxembourgs, who ruled the Bohemian Crown. At first, the townspeople’s lives continued normally, but they were increasingly interrupted by attacks by armed robber knights. During one such attack, the city lost 10 armed guards. In this situation, the town councillors decided to join an alliance of 14 Silesian towns against the robber knights. This all took place in 1398, and it seemed that a long-awaited period of peace would now begin, especially since the city’s privileges were confirmed by King Wenceslaus of Luxembourg. Unfortunately, Bolesławiec was then struck by Hussite raids. As early as 1427, the Hussites seized all the surrounding localities, but the city itself managed to defend itself by paying a ransom. The ransom consisted of excellent beer, widely known for its quality. Two years later, upon hearing that the Hussites were approaching, the wealthy townspeople left Bolesławiec. The city was captured, and in retaliation for the residents’ conduct, a ransom of 900 kopas of Prague groschen was imposed. Hostages were held in Jaroměř in Bohemia as security for the payment. In addition, the Hussites partially destroyed the city; the town gates suffered particularly badly. With great difficulty, the residents of Bolesławiec paid the ransom and gradually began rebuilding their homes. To protect themselves from further raids, they reached an agreement with Lwówek to provide mutual assistance in the event of an attack.
The losses suffered during the Hussite Wars, compounded by fires, were alleviated by the decrees of Emperor Sigismund of Luxembourg, under which Bolesławiec was exempted from taxes and customs duties.
A few years later, the privilege of the salt markets was confirmed. Salt was imported from Poland and Saxony. To obtain additional revenue for the city treasury, the Town Council replaced corporal punishment with financial penalties. The city used these revenues to repay its debts.
The period of peace enabled the city to expand. The vacant plots were quickly built up, and subsequent newcomers had to build their homes outside the line of the city walls. In this way, three suburbs arose along the main roads leading out of the city: Upper, Lower and Mikołajskie.
The Mikołajskie Suburb was inhabited by miners employed at the gold mine. It contained a cloth dye works, a hospital, a pepper mill, a cemetery and three ponds: Upper, Castle Pond, with sluices, and Gallows Pond.
The Upper Suburb lay in the eastern part of the city. It contained a pottery workshop and a shooting range; later, in the 17th century, a brickworks was built there.
The Lower Suburb was the largest. It contained four pottery workshops, a paper mill, a sawmill, a wood-scraping mill, a fulling mill, a “sand mill,” and the “upper” and “lower” mills, that is, the “great mill.”
Public buildings were erected in the city itself. We already have records from 1452 of the operation of a school over which the Town Council exercised the right of patronage. In 1531, construction of a sewage system began. The installations ran behind the plots through covered conduits, and because the city lay on a gentle slope descending westward, the sewage was naturally directed into the Bóbr.
In 1554, the city took over the Dominican monastery and converted it into a hospital. In 1558, the first pharmacy was organized and opened. The reinforcement of the streets had begun as early as the 13th century, by throwing loose stones into the wettest places. From the mid-17th century onward, not only the main thoroughfares but also the side streets were systematically paved. The town councillors also took care of their seat. Construction of a new town hall began in 1525 and lasted 10 years. In later years, the building was embellished by covering the more frequently used rooms with sandstone tiles and paintings.
Like in the Piast era, the residents of Bolesławiec engaged in trade and brewing, but new branches of the economy also emerged. In the mid-16th century, the largest guild was the clothmakers’ guild. Around 700 people practiced this craft. Blacksmithing and locksmithing also played a significant role. The blacksmiths had their own guild, and their substantial growth was undoubtedly connected with increased production at suburban smithies, which supplied large quantities of iron raw material. Pottery workshops were established on the basis of the rich deposits of ceramic clay. However, the potters’ guild was not numerous, and its members were not wealthy. The 1563 register of Bolesławiec residents, which listed homeowners and the quantity of weapons they possessed, makes no mention of potters. The population grew, and in the mid-16th century the city had 3,450 inhabitants. This magnificent period of development was brutally interrupted by external events.
In 1618, an uprising against the ruling Habsburg dynasty broke out in Bohemia. The Thirty Years’ War (1618–1648) began. In its first period, it halted Bolesławiec’s development but did not bring military operations to the city. Only the second period of the war proved catastrophic.
The city’s convenient location on the main road at a ford across the Bóbr led to its destruction during the war. Organized and irregular units of passing troops imposed heavy, and sometimes impossible, contributions on the townspeople. Deprived of legal protection, terrified, decimated and utterly starving, the population left the city, hiding in less accessible settlements. Numerous smallpox epidemics decimated the remaining residents. A great fire in 1642 destroyed the entire built-up area, including the suburbs. After the war, only 80 inhabitants remained in the city. Together with returning townspeople, they began rebuilding it. Reconstruction was hindered, however, by numerous fires and the Habsburgs’ Counter-Reformation policy directed against local Protestants. The city’s population gradually increased, but it did not exceed 3,000 inhabitants until the second half of the 18th century. It was also during this period that the craft workshops destroyed by the war were fully rebuilt.
The turbulent years of Habsburg rule in Silesia ended suddenly in December 1740, when, on the orders of Frederick II, Prussian troops entered these lands. The First Silesian War (1740–1742) began. The excellently armed Prussian forces occupied almost all of Silesia in less than two months. In 1742, under the Treaty of Breslau, Prussia became the sole owner of Silesia. A new chapter in the history of the city on the Bóbr began.