The Saalburg is a Roman fort located on the main ridge of the Taunus, northwest of Bad Homburg, Hesse, Germany. It is a cohort fort, part of the Limes Germanicus, the Roman linear border fortification of the German provinces. The Saalburg, located just off the main road roughly halfway between Bad Homburg and Wehrheim is the most completely reconstructed Roman fort in Germany.
Shortly after the two enclosures, around AD 90, a simple wood-and-earth fort was built to house a numerus. A numerus was a unit of auxiliary troops consisting of 2 centuriae and numbering about 160 men. There is some evidence that the troop stationed at this fort was a numerus Brittonum, i.e. a unit from Britain, but this is not entirely clear.

Late in the reign of Hadrian, c. AD 135, the numerus fort was replaced with a much larger (3.2 hectare) fort for a cohort, a unit of about 500 men. The new castle was reoriented to face the growing Roman city of Nida (now Heddernheim). Originally, it had dry-built wood-and stone walls, which were replaced in the 2nd half of the 2nd century with mortared stone walls and an earthen ramp (147 × 221 m). The reconstructed fort is based on that third and last architectural phase, but reminders of the second phase are visible in the retentura (the back of the fort). Part of the second-phase defensive ditch has also been restored and can be inspected there.

Interior of the assembly hall
The cohort fort was occupied by the Cohors II Raetorum civium Romanorum equitata (2. partially mounted Raetian cohort with Roman citizenship), a partially equestrian 500-men infantry unit, probably under the command of the legionary headquarters at Mogontiacum (modern Mainz). The cohort had initially been stationed at Aquae Mattiacorum (Wiesbaden), had then been moved to the Butzbach fort (ORL 14) and finally to the Saalburg.

The fort existed in that form and with that occupancy until the fall of the German limes in c. AD 260. During the intervening period, the name of the unit is repeatedly mentioned in stone inscriptions, as are the names of some of its commanders.

In the early 3rd century, the situation along the limes became increasingly unsettled. A preventative war under Caracalla, who marched against the Alamanni and their Chatti allies from Raetia and Mogontiacum in AD 213, lowered the Germanic pressure on the border only temporarily. The town of Nida (capital of the regional civitas) was given a defensive enclosure around that time. Already around 233, the Alemanni entered Roman territory again; further major incursions took place in 254 and 260. Eventually, all areas east of the Rhine were lost during the major political and economic crisis of the mid-3rd century. In the course of these events, the Saalburg fort appears to have been abandoned deliberately and without military action.

After the abandonment of the Upper Germanic Limes, the fort was used as a quarry.

Archaeology, architecture

Internal courtyard of the principia
The Saalburg in its final architectural phase, in the form reconstructed today, as a cohort fort typical for this part of the limes, a 147 by 221 m rectangle with 4 gates.

The 3.25 m interior was enclosed by a double ditch and a mortared defensive wall; its external face was whitewashed and painted with a trompe-l’œil pattern of ashlar blocks. On the inside, an earthen ramp was placed along the length of the wall, to enable defenders to access the top. The corners were rounded and not crowned with towers, but all four gates were flanked by two towers each.

The fort was oriented in such a way that its main gate, or porta praetoria faced south-south-east, that is away from the limes but towards Nida. The central structure of the fort was a large principia, a central plaza surrounded by housing or offices for the higher officers, which was flanked by a roofed hall for assemblies of the fort’s garrison. The praetentura (front part of the fort) contained the praetorium (the fort commander’s residence) to the west of the via praetoria, and a large horreum (grain store) to its east. The rest of the fort’s interior, today a park-like area of grass and trees, should be visualised as packed with further buildings: stables, magazines, workshops and, of course, the actual troop quarters, subdivided into contubernia. Two such troop barracks have been reconstructed in the southeast part of the fort. For the general arrangement and terminology of Roman fort architecture, see Castra.


Main gate – foundations and basements of the vicus visible on the left
The Saalburg is not only the most consistently reconstructed limes fort, it is also the only one to have had its vicus (adjacent civilian settlement) partially excavated and preserved. The parts of the vicus visible today are located mostly to the south of the fort, on both sides of the road that linked it with Nida, the regional capital and base of further garrison behind the border.

The village begins immediately outside the main gate, where the ruins of a mansio (an official hostel) and, behind it, of a bath for the soldiers were found. These are followed along the road by the preserved basements and foundations (partially reconstructed) of residential houses and of – as believed in the time of the excavations – a mithraeum, a shrine to the Mithras, a deity popular among the Roman army.

The fort’s bath was relatively large and quite elaborately designed to have all the main features of Roman Thermae. It has an apodyterium (changing room), a frigidarium (cold bath), two tepidaria (lukewarm baths’, a caldarium (hot bath) and a sudatorium (sauna). The complex was heated from the praefurnia (firing places); and all rooms except the apodyterium and frigidarium were served by a hypocaust system (underfloor and wall heating).

Archaeologists assume that the overall complex (fort and vicus) housed a population of up to 2,000 (500 soldiers, 1,500 civilians).