Silva Carbonaria, the "charcoal forest", was the dense old-growth forest of beech

Beech

Beech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...

 and oak

Oak

An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

 that formed a natural boundary during the Late Iron Age through Roman times into the Early Middle Ages

Early Middle Ages

The Early Middle Ages was the period of European history lasting from the 5th century to approximately 1000. The Early Middle Ages followed the decline of the Western Roman Empire and preceded the High Middle Ages...

 across what is now Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

. The forest naturally thinned out in the open sandy stretches to the north and formed a barrier—trackless to the outsider—on the heavier soils to the south. Yet further to the south, the higher elevation and deep river valleys were covered by the even less penetrable ancient Arduenna Silva, the deeply folded Ardennes

Ardennes

The Ardennes is a region of extensive forests, rolling hills and ridges formed within the Givetian Ardennes mountain range, primarily in Belgium and Luxembourg, but stretching into France , and geologically into the Eifel...

, which are still forested to this day. The Silva Carbonaria was a vast forest that stretched from the rivers Senne

Senné

Senné is a village and municipality in the Veľký Krtíš District of the Banská Bystrica Region of southern Slovakia.-External links:*http://www.statistics.sk/mosmis/eng/run.html...

 and the Dijle

Dijle

Dyle or Dijle or historically the River Dyle in English, is a river in central Belgium, left tributary of the Rupel. It is long. It flows through the Belgian provinces of Walloon Brabant, Flemish Brabant and Antwerp...

 in the north to the Sambre

Sambre

The Sambre is a river in northern France and Wallonia, southern Belgium, left tributary of the Meuse River. The ancient Romans called the river Sabis.-Course:...

 in the south. To the east Silva Carbonaria extended to the Rhine, where near Cologne in 388 CE the magistri militum praesentalis Nannienus and Quintinus counterattacked a Frankish incursion across the Rhine in the Silva Carbonaria. Its northern outliers reached the then marshy site of modern Brussels

Brussels

Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

.

Roman road

A great Roman road

Roman road

The Roman roads were a vital part of the development of the Roman state, from about 500 BC through the expansion during the Roman Republic and the Roman Empire. Roman roads enabled the Romans to move armies and trade goods and to communicate. The Roman road system spanned more than 400,000 km...

 forming a "strategic axis" linked the Rhine crossing at Cologne

Cologne

Cologne is Germany's fourth-largest city , and is the largest city both in the Germany Federal State of North Rhine-Westphalia and within the Rhine-Ruhr Metropolitan Area, one of the major European metropolitan areas with more than ten million inhabitants.Cologne is located on both sides of the...

  with Maastricht

Maastricht

Maastricht is situated on both sides of the Meuse river in the south-eastern part of the Netherlands, on the Belgian border and near the German border...

, where it crossed the Maas at the head of navigation. Skirting the northern edges of the Silva Carbonaria, it passed through Tongeren, Kortrijk

Kortrijk

Kortrijk ; , ; ) is a Belgian city and municipality located in the Flemish province West Flanders...

 and Cambrai

Cambrai

Cambrai is a commune in the Nord department in northern France. It is a sub-prefecture of the department.Cambrai is the seat of an archdiocese whose jurisdiction was immense during the Middle Ages. The territory of the Bishopric of Cambrai, roughly coinciding with the shire of Brabant, included...

 to reach the sea at Boulogne

Boulogne-sur-Mer

-Road:* Metropolitan bus services are operated by the TCRB* Coach services to Calais and Dunkerque* A16 motorway-Rail:* The main railway station is Gare de Boulogne-Ville and located in the south of the city....

. The highway was the main east–west route in a landscape where the river valleys, tributaries of the Meuse

Meuse

Meuse is a department in northeast France, named after the River Meuse.-History:Meuse is one of the original 83 departments created during the French Revolution on March 4, 1790...

 and the Scheldt

Scheldt

The Scheldt is a 350 km long river in northern France, western Belgium and the southwestern part of the Netherlands...

, tended southwest to northeast. It remained viable through the Early Middle Ages

Early Middle Ages

The Early Middle Ages was the period of European history lasting from the 5th century to approximately 1000. The Early Middle Ages followed the decline of the Western Roman Empire and preceded the High Middle Ages...

 as the chaussée Brunehaut, the "Road of Brunehaut". As a public work its scale had become unimaginable in the Middle Ages: the chronicler Jean d'Outremeuse

Jean d'Outremeuse

Jean d'Outremeuse or Jean des Preis was a writer and historian who wrote two romanticised historical works and a lapidary....

 solemnly related in 1398 that Brunehaut

Brunhilda of Austrasia

Brunhilda was a Visigothic princess, married to king Sigebert I of Austrasia who ruled the eastern kingdoms of Austrasia and Burgundy in the names of her sons and grandsons...

, wife of Sigebert I

Sigebert I

Sigebert I was the king of Austrasia from the death of his father in 561 to his own death. He was the third surviving son out of four of Clotaire I and Ingund...

, had built this wide paved road in 526, and that it was completed in a single night with the devil's aid.

The Silva Carbonaria as a border

When the Franks

Franks

The Franks were a confederation of Germanic tribes first attested in the third century AD as living north and east of the Lower Rhine River. From the third to fifth centuries some Franks raided Roman territory while other Franks joined the Roman troops in Gaul. Only the Salian Franks formed a...

 settled on the left bank of the Rhine in the fourth century, the Salian Franks

Salian Franks

The Salian Franks or Salii were a subgroup of the early Franks who originally had been living north of the limes in the area above the Rhine. The Merovingian kings responsible for the conquest of Gaul were Salians. From the 3rd century on, the Salian Franks appear in the historical records as...

 rapidly occupied the flat open country with its coastal marshes, and the mixed tribal groups that Romans called Belgae

Belgae

The Belgae were a group of tribes living in northern Gaul, on the west bank of the Rhine, in the 3rd century BC, and later also in Britain, and possibly even Ireland...

 withdrew to the wooded south; there the Romanized Celts—the "Wala" or "strangers" to the Germanic Franks—continued speaking a Late Latin

Late Latin

Late Latin is the scholarly name for the written Latin of Late Antiquity. The English dictionary definition of Late Latin dates this period from the 3rd to the 6th centuries AD extending in Spain to the 7th. This somewhat ambiguously defined period fits between Classical Latin and Medieval Latin...

: their label as Wala survives in Walloon

Walloons

Walloons are a French-speaking people who live in Belgium, principally in Wallonia. Walloons are a distinctive community within Belgium, important historical and anthropological criteria bind Walloons to the French people. More generally, the term also refers to the inhabitants of the Walloon...

. In the past the Romance-Germanic linguistic division that marks Belgium to this day has been perhaps too facilely linked to these geographic parameters.

The Silva Carbonaria is mentioned in the Salic Law

Salic law

Salic law was a body of traditional law codified for governing the Salian Franks in the early Middle Ages during the reign of King Clovis I in the 6th century...

 of the Franks, where it marked "the boundary of the territories occupied by the Frankish people". For a time in the sixth century, the Silva Carbonaria formed a barrier between the West Frankish kingdom of Clovis

Clovis I

Clovis Leuthwig was the first King of the Franks to unite all the Frankish tribes under one ruler, changing the leadership from a group of royal chieftains, to rule by kings, ensuring that the kingship was held by his heirs. He was also the first Catholic King to rule over Gaul . He was the son...

 and the East Frankish kingdom of Sigebert the Lame, centred on Cologne, until he was defeated some time after 507, and Clovis joined the two kingdoms, which however retained their separate identities throughout the rule of the Merovingians.

Extensive tracts of the untamed woodlands belonged to monasteries. The Benedictine Abbey of Lobbes lay in the Silva Carbonaria and that of Saint Foillan

Foillan

Saint Foillan is an Irish saint of the seventh century.- Family :Foillan was the brother of Saints Ultan and Fursey. He is described as the 'uterine brother' of Fursey, meaning that they had the same mother but not the same father...

, in the Sonian Forest

Sonian Forest

The Sonian Forest is a forest that lies across the south-eastern part of Brussels, Belgium.The forest lies in the Flemish municipalities of Sint-Genesius-Rode, Hoeilaart, Overijse and Tervuren, in Uccle, Watermael-Boitsfort, Auderghem and Woluwe-Saint-Pierre in the Brussels-Capital Region and in...

 (Forêt de Soignes/Zoniënwoud) not far from Nivelles

Nivelles

Nivelles is a Walloon city and municipality located in the Belgian province of Walloon Brabant. The Nivelles municipality includes the old communes of Baulers, Bornival, Thines, and Monstreux....

.

Economic importance

The charcoal

Charcoal

Charcoal is the dark grey residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis, the heating of wood or other substances in the absence of oxygen...

—which gave the forest its name and into which the once seeming inexhaustible woods were slowly converted—was required to fuel the scattered smelting furnaces that forged the plentiful iron found in outcroppings laid bare by riverside erosion. Even before the Romans arrived, iron weapons forged in the Silva Carbonaria were traded by the Belgae to their cousins in the southeast of Britain. In the High Middle Ages further woodlands were cleared. Today the most significant remnant of the Silva Carbonaria is the Sonian Forest

Sonian Forest

The Sonian Forest is a forest that lies across the south-eastern part of Brussels, Belgium.The forest lies in the Flemish municipalities of Sint-Genesius-Rode, Hoeilaart, Overijse and Tervuren, in Uccle, Watermael-Boitsfort, Auderghem and Woluwe-Saint-Pierre in the Brussels-Capital Region and in...

, preserved because it had been set aside as a noble hunt. At the start of the nineteenth century the area of this remnant of the primeval forest still covered about 100 square kilometres, but due to timber cutting its area has diminished to its current protected area of 44.21 km².