For several centuries, the fortress and garrison shaped the development of Küstrin. They brought economic prosperity but also sieges and two total destructions. The construction of the fortress began in the 16th century under Margrave Johann of Brandenburg. Over time, the fortress underwent many changes due to the development of offensive weapons and fortification techniques. Küstrin was considered a "soldier city," where several regiments were stationed. At the end of January 1945, when World War II had long been decided, the city was declared a fortress. When Soviet troops reached the city on January 31, 1945, a 59-day siege began. Küstrin was meant to be the "cornerstone" of the German defense along the Oder. The soldiers of the fortress were far from meeting this claim. Nevertheless, they prevented the advance for many weeks.