The peninsula projecting into Lake Bnińskie (and called Szyja by archaeologists) was the site of a long-standing settlement three times. At the turn of the Bronze Age and the early Iron Age, people of the Lusatian culture used the natural defensive settlement in its southern part (which at the time was an inshore island). The second period of intensive settlement of the peninsula was the 940s, when a strongly fortified early Piast stronghold was erected – it was used (with a break of 160 years) until the beginnings of the 13th c. In the mid-13th c., a dwelling on a mound was erected at the base of the peninsula to become home to castellans until Bnin was granted a municipal charter based on the Magdeburg rights between 1386 and 1395.