The walls surrounding the medieval city were erected around 1280 in the place of the wood and earthen fortifications built immediately after the settling. The new fortification had a roughly circular shape. The walls were some 1,700 metres long and they walled in an area of ca. 21 hectares. The wall rested on a stone foundation and was made of ceramic bricks laid in Venedic pattern and held by lime - based mortar. Its thickness was between 1 and 1.2 metres. There was a battlement on its top and below it on the inside there was a wooden gallery for the defenders. In its highest sections the wall measured 11 metres.
Some 35 watchtowers placed every 35-40 metres from one another fortified the wall. Their number and position made the 14th century Poznań one of the best - fortified cities in Poland. The square watchtowers were one storey higher than the wall and they opened toward the city. However, as early as in the first half of the 15th century the watchtowers started to be modified to close from the inside. The watchtowers had names, some from the trade whose members held patronage over them (such as the Tailors Watchtower or the Butchers Watchtower), others, like the Dominican Friars Watchtower, after the people who used them.
There were four gates leading into the city: Wroniecka Gate in the north, Wielka and Wodna gates in the east and Wrocławska Gate in the south. Next to the gates there were several doors for people on foot, made in the walls mostly in the 15th and 16th centuries.
At the beginning of the 15th century, when advances in artillery rendered old fortifications ineffective, the city walls started to be modernized. The moats fed by the water from Bogdanka and Struga Karmelitańska were cleaned and deepened. Between 1431-33, a second wall was built on the outside of the first. It formed a ring around most of the western, northern and southern limits of the city. Only the part of the city flanked by the Warta River (from the Dominican Church to the Wrocławska Gate) had a single wall. Two new defensive features were added: a tower situated between the Wrocławska Gate and the castle, and a barbican near the Wroniecka Gate. The city's defensive system took its final shape in the early 16th century. However, over the next two centuries it was to lose its military importance. The walls, partially destroyed during wars, were only perfunctorily repaired and fortified. In 1797 the Prussians began a systematic demolition of the walls, a process that lasted until the middle of the 19th century.
All we can see today are small remnants of the old fortifications. The only bigger fragment of the older, inside ring of the walls is the rebuilt square watchtower near the old Dominican monastery (in the back of Masztelarska Street). Near the watchtower, at the junction of Masztelarska and 23 lutego streets, there is a corner watchtower, a remnant of the outside line of fortifications discovered in 1947 among the ruins of a destroyed townhouse. There is another fragment of the old wall near Ludgarda Street. The section of the wall with a shooting gallery situated in Podgórna Street dates from the early 18th century.
Recently, significant remnants of medieval walls and city gates have been discovered during archaeological work on the old gates: Wroniecka, Wodna and Wrocławska. In several places, such as Paderewski, Wroniecka, Wielka, Wodna and Wrocławska streets, red paving stones mark the course of the old walls.
In the 19th century, the Prussians surrounded Poznań with yet another, much bigger ring of walls and fortifications.