The form of present tower continues traditions of medieval fortified building. Very similarly might have looked towers protecting gates of early-medieval Slavic castles and towers that used to be an element of medieval knights' seat. Holes in the floor of "izbica" made possible striking an invader that was at the tower's bottom. This kind of function was not used in towers of wooden churches but still the construction of tower outlasted in many sacral monumental buildings. In the premises of Opole Province there are these kind of church towers in Bierdzany and Stare Olesno only.