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The Wall – From fortified post to world heritage site

This article is about a famous wall, a wall with such an important history that it has been designated a World Heritage Site. But what wall is it? See if you can figure out the name of the Wall from the clues in this article. Not to worry … by the end of the article you will know what in the world you’re reading about!

Most, but not all, of the rocks in the area where the Wall is located are layered sedimentary rocks – limestone, mudstone, sandstone and coal. There is one noticeably different rock in that part of the world – a very hard, dark grey, nearly horizontal bed of crystalline igneous rock.

Some 295 million years ago, movement of the Earth’s crustal plates caused molten rock deep within the Earth to rise upwards. The magma was forced between the layered rocks, and when it cooled and solidified it formed rock referred to by geologists as dolerite.

{{image2-a:r-w:250}}After millions of years of erosion, the dolerite, some of it as much as 30 metres thick, was exposed at the land surface. Locally, quarrymen referred to the rock formation as the Whin Sill. The rock is resistant to erosion and the Whin Sill is marked by spectacular cliffs, long ridges, and north-facing crags.

About 122 AD, a Roman emperor ordered the 120 kilometre long Wall and fortifications to be built which, according to Scriptores Historiae Augustae, was “to separate the Romans from the barbarians”.

Other scholars speculate that the Wall was to discourage raiding parties and control trade and immigration. Long stretches of the eastern part of the Wall strategically took advantage of the Whin Sill cliff lines. The Wall was essentially completed within six years, and was the most heavily fortified border in the Roman Empire.

The eastern part of the Wall, which was about three metres wide and five to six metres high, was made from squared stone blocks. Rock from the Whin Sill could not easily be dressed into blocks, so the local sandstone became the preferred building material. However, the Whin Sill rock did find a home in the rubble core of the Wall. The western part of the Wall was made of turf. In total, the Wall extended across the entire width of northern Great Britain.

Following the emperor’s death in 138 AD, the new emperor Antoninus Pius had a new wall (the Antonine Wall) constructed about 160 kilometres to the north and demoted the Wall to a support role.

The Romans were unable to conquer the northern tribes, so when Marcus Aurelius became emperor, he ordered the abandonment of the Antonine Wall and the reoccupation of the Wall, which remained occupied until Roman troops withdrew from northern Britain, circa 383 AD.

Once abandoned, the Wall became an easy source of ready-made building blocks. Much was reused in other local buildings and for road construction in the 18th century. Preservation of the Wall began in the 19th century and its rescue is largely credited to John Clayton, an antiquarian and the town clerk of Newcastle upon Tyne, who purchased large sections of the land on which the wall stood to protect it from plundering.

In 1987, Hadrian’s Wall – named after the Roman emperor Hadrian who ordered its construction – was declared a World Heritage Site.

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