The Pleissenburg (German: Pleißenburg) was a historical building in the city of Leipzig in Saxony which is in modern-day Germany.

After the severe destruction caused by the siege of the Schmalkaldic War, Maurice, Elector of Saxony (1521–1553) had the castle demolished in 1548 and rebuilt as a triangular fortress in 1549 under the direction of Hieronymus Lotter[1] (1497–1580).

The new Pleissenburg was attached to the city's fortification system and separated from the main walls by its own moat, so that it assumed the function of a citadel.

[5] In the Thirty Years' War, the attack of the Catholic League army under Johann Tserclaes, Count of Tilly on the Electorate of Saxony began with the capture of the Pleissenburg on 14 September 1631.

[6] After the Thirty Years' War and the capture of Leipzig by the Swedes in September 1706, the Pleissenburg gradually lost its military importance.

In 1784 the chemist Christian Gotthold Eschenbach (1753–1831) founded the first chemical laboratory of the Leipzig University in the Pleissenburg.

[9] All that remains of the Pleissenburg is the tower designed by Hieronymus Lotter as the base for the summit of the New Town Hall, which is visible from afar.