Palatium in Poznań - princely palace from age of early Piast dynasty. Later inhibited by kings, built in the western part of Poznan Cathedral Island probably in the mid-tenth century. Palace was under the present church of the Blessed Virgin Mary, had a rectangular shape and was set on the north-south axis. - dictated by the terrain conditions (the island is made of unstable sands and clays). According to the latest, continuously conducted archaeological discoveries the palace had dimensions of 27.25 m to 11.70 m to 11.90m.
Castle and the Cathedral Island suburb were destroyed during the invasion of the Czech prince Břetislav I, probably in early 1039 years. The cathedral was rebuilt, but rebuilding the palace was postponed for later moment (and never really done). Currently in that place you can find a church of Blessed Virgin Mary.