Historical sources first mention defensive walls in Biecz in 1399. It was then that King Władysław Jagiełło called on the townspeople and people from around Biecz to repair the city fortifications damaged by the passage of time. The construction of the defensive walls in Biecz can be linked to the time of Kazimierz Wielki (Casimir the Great), who allocated significant sums to grand construction projects and to improving the country's defences. The saying 'Casimir the Great found Poland wooden, and left it made of stone' ('Kazimierz Wielki zastał Polskę drewnianą a zostawił murowaną') is well-known for a reason. A border fortress, the city, was exposed to the risk of invasion. Walls had to be built around it soon after it was established. The powerful city walls were strengthened by 16 defensive towers, three of which have survived to this day: the Rajcowska and Kowalska towers and the Gothic bell tower near the Corpus Christi collegiate church. Biecz also had one of the very few barbicans in Poland. Each tower was assigned a craft guild to defend it. In the case of this tower, it was the blacksmiths' ('kowal') guild, hence its name – Kowalska Tower (Blacksmiths' Tower).