The Znaimertor in the Znaimerturm was, together with the Nalbertor, one of the two city gates of the city of Retz in Lower Austria.
The city of Retz was founded in the immediate vicinity of Retz old town and laid out according to plan. The two city gates in the Znaimerturm and in the Nalberturm also date from around 1300.
In the course of the reconstruction of Retz after the conquest by the Hussites in 1425, so-called gate works were built in front of the city gates. Outside the city walls, the street in front of the Znaimertor led through a kinked doorway, which was interrupted by a gate and secured by another gate on the gate wall.
In 1552 a bell is mentioned on the Znaimerturm and in 1553 a tower clock.
In view of the danger posed by the Swedish troops, the imperial order was issued in June 1639 to put the city of Retz in a state of defense. On this occasion, the Znaimer and Nalberturm were equipped with tiled roofs. The Nalbertor was closed, the Znaimertor was the only way to leave or enter the city. Around 1730 the partially desolate city wall was repaired and in 1733 the street in the Znaimertor was paved. Since the Znaimerturm was also dilapidated, it should be demolished and replaced by a smaller tower. In 1736 the tower was finally renovated and given the hipped roof in its current form.