Tower X forms part of Pompeii’s defences and stands along the northern section of the city walls, between Vesuvius Gate and Tower XI, known as the Tower of Mercury. This stretch of fortifications, on the northern boundary of Regio VI, is among the best preserved in the entire circuit and offers a particularly clear picture of how the city’s defences were organised.
The tower belonged to the group of twelve towers added to the walls during the major strengthening of the fortifications in the early 1st century BC. This work preceded the siege of 89 BC, when Pompeii, which had sided against Rome in the Social War, was attacked by the troops of Lucius Cornelius Sulla. During this period, the defensive system was extensively reorganised to meet new methods of warfare.
Tower X shares its architectural type with Towers XI and XII. The original structure had three levels, connected by internal staircases and supported by vaults. An entrance on the side facing the city provided access to the stairs, while side openings linked the upper levels to the wall walk.
The lowest level contained a large barrel-vaulted chamber, connected to a corridor leading to the postern, a small doorway at the base of the tower opening to the outside of the city. This passage allowed defenders to leave the fortifications quickly without using one of the main city gates.
Numerous arrow slits pierced the tower’s walls, enabling defenders to observe and control the ground outside while remaining protected within the building. Some are still clearly visible in the northern and western walls; others were altered or blocked during later changes to the structure.
Tower X also retains important traces of its original plaster coating. When the structure was uncovered in the late 19th century, some of its First Style decoration remained remarkably well preserved. The towers’ surfaces were therefore not simply left as exposed masonry: they could be plastered and articulated to imitate monumental construction in large, regular blocks.
One of the most intriguing discoveries is a graffito bearing Sulla’s name, already recorded in the late 19th century on the plaster near one of the stairway openings. The Roman general’s name initially led scholars to connect the inscription directly with the siege of 89 BC. Although the graffito is certainly evocative, modern studies stress that no evidence establishes a direct connection with the military operations or Sulla’s personal presence at the tower.
Archaeological investigations at Tower X also played an important role in reconstructing the history of Pompeii’s walls. In 1898, Antonio Sogliano began systematically clearing the northern part of the tower. In the following years, excavations continued westwards, gradually revealing the stretch of fortifications between Towers X and XI.
Studies have shown that the northern fortifications resulted from a long succession of building phases. Earlier curtain walls of squared stone blocks have been identified beneath the later structures, while the work of the early 1st century BC substantially transformed the defences by adding the large towers built in opus incertum.
Tower X occupied a particularly significant position just west of Vesuvius Gate, one of the city’s main northern entrances. In the Augustan period, this area gained further importance with the construction of the nearby Castellum Aquae, the large reservoir that received water from the aqueduct and distributed it through the city’s water network. The ancient fortifications thus came to form the setting for infrastructure serving primarily the city’s civilian life.
After the Roman conquest and the foundation of the colony in 80 BC, the walls gradually lost their original strategic role. The towers nevertheless continued to define the city’s skyline, and some were maintained, altered or adapted to new uses. Tower X also preserves evidence of changes to openings and internal routes that departed from its original military arrangement.
The earthquakes that affected Pompeii during the 1st century AD, followed by the eruption of AD 79, severely damaged the upper parts of the towers. Despite these losses, a substantial part of Tower X’s standing structure survives, together with many features of its internal layout, making it particularly valuable for understanding the original appearance of the fortifications.
Major excavation and restoration work took place in 1934, when the tower and the surrounding stretch of walls were repaired and consolidated. These interventions helped shape the appearance by which this area was known for much of the 20th century.
More recently, the Archaeological Park of Pompeii carried out a new project to restore and improve access to the entire northern stretch between Tower X and Tower XI, or the Tower of Mercury. The work addressed the masonry, stone surfaces and tuff elements, as well as the paths and upper wall walk.
The stretch between the two towers is now one of the most informative places for understanding Pompeii’s system of walls. From the upper wall walk, visitors can see the city interior, Vesuvius and the surrounding countryside at the same time, immediately appreciating the strategic value of the position chosen by the ancient builders.
Tower X and the city walls therefore provide exceptional evidence of fortified Pompeii. The multiple levels, arrow slits, postern, surviving First Style plaster and different phases of the walls allow us to reconstruct both the tower’s military operation and the gradual transformation of the fortifications after the city’s definitive incorporation into the Roman world.
View this location on the Pompeii Buildings and Places map