Secular Structures
The Gothic style influenced defensive structures. Buildings erected during the reign of Kazimierz Wielki (Casimir III the Great) (1333–1370) were made entirely of brick. The administrator’s (a castellan or governor) house stood within the outer walls, as did the tower, which was the last line of defence in case of attack. Given the flatness of Wielkopolska, these places had to exploit river forks, backwaters and marshes for defence.
Castles
The remains of several castles built during this period to bolster the defence of the realm’s western borders still survive. The 20-metre tower and fragments of the peripheral walls of a castle from c. 1335 (later rebuilt) still stand in Bolesławiec nad Prosną (Wieruszów County). The octagonal tower and part of the walls of a castle from the 1st half of the 14th century still survive in the centre of Ostrzeszów. The pre-14th C. tower in Koźmin was embedded in a later residence with a shoe-shaped layout. The striking ruins of the castle in Koło (viz. the lower part of the tower and considerable sections of the walls), built after the mid-14th century, are situated right on the Warta outside the city.
The function and defensive qualities of a medieval castle are most evident in Borysławice Zamkowe (Koło County). The remains of a defensive residence, erected c. 1425 for Abp. Wojciech Jastrzębiec and most probably rebuilt in the 1st half of the 16th century, have survived.
As artillery development made brick walls easy to shatter, earthen fortifications were exclusively used for militarily significant buildings from the 16th century. The remains of the fortress in Zbąszyń are the best preserved (albeit only partially) of this type of fortification in Wielkopolska.
Defensive Walls
Research has revealed that 12 Wielkopolska cities were fortified by the beginning of the 15th century. These only exist in a vestigial state today. None has survived intact, e.g. there are no keeps or gates of the kind commonly seen in Silesia, Pomerania and Małopolska, and the course the walls once took is only apparent from the layout of the streets. Most of the fortification remains are in Wschowa. The walls here were completed before 1409 and have a circumference of 900 m, of which several lengthy stone and brick fragments remain. Recently, these have been beautifully offset by the park where the moat used to be. The Evangelical church adapted the former Brama Polska (Polish Gate) tower for use as a belfry.
Quite a few city wall fragments have survived in Kalisz, where they have been used to build townhouses and fences delineating property boundaries. The 90-metre chunk of wall near the cathedral is the best known.
There are even fewer fortification remains in other cities. Poznań only has five tiny fragments from the 13th and 14th centuries, of which the portion of the “bastille” wall in ul. Masztalarska is the most impressive. A fragment of a former keep preserved in the walls of the Dominican (now Salesian) monastery in the same street was recently uncovered and investigations have allowed the basement of the former Brama Wroniecka (Wroniecka Gate), and the chunk of the defensive wall adjoining it from the west, to be displayed.
