The Drususstein (Drususstone) is a nearly 20 meters high, masonry block of Roman origin on the grounds of the citadel of Mainz, Germany. It was originally cast in marble. Researchers now largely accept that this is the structural remnant of the cenotaph mentioned by writers like Eutropius and Suetonius, erected in 9 BC by Roman troops in honour of the deceased general Drusus, in Mogontiacum (now Mainz). During the early days of the Principate the Drususstein was the starting point for elaborate memorial services in honour of Drusus, and the centre of the imperial cult in Mogontiacum. After being robbed of its marble casing in the early Middle Ages, it served as a watchtower in the fortifications of the city in the 16th century. For that purpose a staircase and doorframe were made in the structure, which had been up to that point a massive building. Besides the pillars of aqueducts and the stage of the theatre, the Drususstein is one of the few remaining visible reminders of Roman Mogontiacum. Together with the Column of Igel, it is the only funerary monument north of the Alps dating from antiquity that remains in its original location.