At the end of the 14th century three gates were leading into the city: the Michael’s – Northern gate, the Vydrica – Western gate and the Laurinc – Eastern gate. In the 15th century another smaller gate, called Fishermen’s gate was built, leading to the South to the Danube river, and the gates were fortified by embankments by the order of Žigmund Luxembourg after invasion of the Hussites. The fortification walls were made of stone, 130 to 160 cm thick. Their final appearance comes from the first half of the 16th century, when the fortification was strengthened for fear of Turkish raids. In modern era the city walls were loosing their importance and by the order of the empress Maria Theresa in 1775 a large part of the city walls was demolished or built-up, the moats were filled up for hygiene reasons, and the city was integrated with suburbs.
The Michael’s gate and a part of city walls along the Staromestská street with two towers, Bird tower and Northwestern Tower, are the only pieces of the original city fortification preserved till today. During the construction of the SNP bridge (Bridge of the Slovak National Uprising) in the 70-ties of the 20th century a large part of the fortification was uncovered during the demolition of houses in today’s Staromestská street. In 80-ties and 90-ties of the 20th century fortification was renovated to the present form.