Forum Hadriani – Voorburg. A capital for the Cananefates

Establishment of town and granting of city charter

The town in Voorburg probably started life in the mid-first century AD as a small population centre beside Corbulo’s Canal. After the formation of the civitates (administrative regions) in the province of Germania Inferior between AD 82 and 90, the town was designated a civitas capital. Somewhere between AD 120 and 151 it was granted a city charter, which meant it could call itself a ‘municipium’. From that point on, its new name was Municipium Aelium Cananefat(i)um (abbreviated to MAC). It is not clear whether the name Forum Hadriani predates MAC. Indeed it is quite possible that both names were used simultaneously. We do however know that the name Forum Hadriani was used for longer. It appears on a Late-Roman road map, and was eventually handed down to us via a Medieval copy of this map.

Building phases in the town

A settlement beside the canal

There are several phases to the Roman town in Voorburg, best known by the name Forum Hadriani. First, a small population centre was built on the site of an indigenous settlement, quite possibly because of its position beside Corbulo’s Canal. Traces of this early phase are very rare. In fact the history of the town can only really be properly traced from the end of the first century.

The town grows

019kaartforumhadrianDuring the reign of Domitianus (c. AD 80-90) the core of the town probably lay at the site of the later bath house. A building made completely or partially of stone probably stood here, indicating that it had a special function. The orientation of buildings and streets would later change. The small town stood on a main road that had recently been laid, transecting the traces of the old indigenous settlement. The early town straddled both sides of the road. Three adjacent rectangular houses from this phase have been found. The plots were an average of around six metres wide and fifteen metres deep, with their short side to the street. Behind the houses was a yard containing a well. The inhabitants also buried their waste behind their homes, as evidenced by a number of waste pits. The exact size of the early town is not known, as only sporadic traces from this period have been found. However, finds from the site suggest that it grew in importance during this period. Since the town lay beside Corbulo’s Canal, it might also have housed a small base for the Roman fleet. If there was a harbour, however, it cannot have lasted long. Recent research has shown that Corbulo’s Canal had silted up by AD 200, making navigation impossible.

Blocks of houses in a large town

VoorburgplatBuitendorpThe town did not really begin to flourish until after it had been granted a city charter (somewhere between AD 120 and 151). It had a classic rectangular grid pattern, the hallmark of a true Roman town. For a long time, archaeologists thought they had found a military site. The town consisted of blocks of houses (insulae) and a number of public buildings. One of the blocks has been almost completely excavated. Long narrow houses stood on two sides. The houses were adjacent to each other, with their short side facing the street. An arcade  running in front of all the houses gave the appearance of a single façade. Behind the houses were yards surrounded by fencing, which met at the back. At the end of the yards, against the fencing, many waste pits have been found. Recent excavations have also revealed wells in the back yards. Most of them used an old wine barrel as facing, but in one of the wells the walls were made of parts of a recycled dugout canoe. In some streets remains of a wooden road surface that must have been laid around the mid-second century have been found.

In the second half of the second century the town was surrounded by a stone wall. About a century later, around AD 270, the town appears to have been almost entirely abandoned.

Phases at Forum Hadriani – Voorburg

To c. AD 47

Indigenous settlement

c. AD 47

Corbulo’s Canal dug. Construction of a (small?) population centre beside the canal at the site of the later town

c. AD 90

Voorburg becomes the official civitas capital of the Cananefates

from c. AD 121/122

Final layout with rectangular grid pattern and blocks of housing. At initiative of emperor Hadrian?

between AD 121 and 151

City charter granted: new name Municipium Aelium Cananefatium. Also known as Forum Hadriani

AD 138-161

Major construction work

c. AD 275

Town abandoned

Public buildings

We currently have too little information for an extensive discussion of the public buildings in Forum Hadriani. We do however know about the bath house and the town wall.

The bath house

The bath house at Forum Hadriani in Voorburg was excavated in the early 19th century by the world’s first professor of archaeology, C.J.C. Reuvens. He meticulously recorded his finds and even measured the height of the features, which was very unusual for that time. Since he had so little material for comparison, it was difficult for him to interpret the features. But his precise records and beautiful drawings have allowed them to be interpreted more recently. The bath house was probably built between AD 120 and 150. The remains consist mainly of stone foundations, fragments of wall paintings and other finds. Little remained of the standing walls. It appears to have been a bath house of the ‘row type’, like the bath house in Heerlen. On leaving the changing room one would first enter the frigidarium, the cold plunge pool. Beyond that lay the tepidarium, where the temperature was more pleasant. The final pool in the row was the caldarium, the hot water bath. The water in this room was heated by a furnace behind the caldarium. The bathing rooms were along one side of an inner courtyard. On the other side there was probably a water tower. The walls of this structure have heavier foundations, and buttresses were even added at a later stage to support the great weight of the water. There was also a large public toilet in the building, which was probably also used by people entering from outside the bath house.


The town wall

In the second half of the second century a stone wall was built around the town. Prior to this the town had been surrounded by an embankment and a moat. A second moat was dug next to the first when the stone wall was built. There were also stone gateways in the wall, one small and one large example of which have been excavated to date. The style of the gates supports the dating in the second half of the second century. From the end of the second century, gateways protruded from the outside of the wall. However, the two gates in Voorburg barely protrude, if at all, suggesting that they were constructed before the end of the second century.


Houses and yards

Throughout the Roman period, the main material used for building in the Netherlands was wood. Walls consisted of wattle covered with daub. Buildings in town were often rectangular, with their short side facing the street. The same type of houses are also found in smaller rural towns. Traces found in Forum Hadriani show a row of rectangular wooden houses and their internal layout. There were wells in the yards behind the houses. Along the front of the houses ran an arcade forming a single roof.

Stone buildings

The use of stone for building really only took off in the second century. Natural stone had to be imported from far away, as there was no stone suitable for building in the Netherlands. Wooden houses were only gradually replaced by stone structures, so wooden and stone buildings would have stood alongside each other.

Houses of the rich

There will most probably have been larger houses in Forum Hadriani. Unfortunately, we do not know what they looked like, as the traces found give us too little information.

voorburg houten huis


For more information about Forum Hadriani, visit Museum Swaensteyn in Voorburg or Museon in The Hague.


Bazelmans, J.G.A. en D.H. de Jager, 2006, Forum Hadriani. De Verloren stadVan Romeinse stad tot monument. Utrecht

Buijtendorp, T., 1982, Een Romeinse stad bij Voorburg-Arentsburg. Een interpretatie. Westerheem 31, 142-163

Buijtendorp, T., 1984, Nieuw onderzoek naar Forum Hadriani. Westerheem 33, 1984, p. 116-124

Buijtendorp, T., 1987, Periodisering van Romeins Voorburg. Westerheem 37, 1988, 107-117

MUST & B. Colenbrander (red), 2005, Limes Atlas. Rotterdam.

Waasdorp, J.A. 2003, IIII M. P. naar M. A. C. Romeinse mijlpalen en wegen. (Haagse oudheidkundige publicaties nr. 8) Den Haag.