Construction began in 1230 and, 300 years later, the top floor of the tower was added along with the late Gothic eaves balustrades and arcade arches of the gallery. The steep roof with the lantern dates back to 1708. Measuring 55 metres in height, it is one of Germany's tallest and most important city gates. The side facing the town has an impressive structure, the arrow slits on the west side hint at the defensive function of the tower.
There is an iron clamp on the northern side of the Old Gate passage. It represents the standard Speyer measurement, the 28 cm tall Speyer "Normalschuh" ("standard shoe"), which was used to measure all things for every trader in Speyer. Luckily, the tower survived the destruction of the city in 1689 and was thus preserved as one of the few remnants of the medieval city fortress.