Anastasian Wall

Listen for a moment. Wind moves through oak and beech. Somewhere a woodpecker taps. Under the leaves, the ground rises into a long, low ridge. If you brush away the moss, you find cut stone and old grey mortar. You are standing on the line of one of the great defensive works of the late Roman world. Most of it is now covered by forest, and few people come to see it.

This is the Anastasian Wall, also called the Long Walls of Thrace. It was built in the late fifth century, around 1,500 years ago. At that time Constantinople, today's Istanbul, was the capital of the Eastern Roman Empire. Historians often call that state the Byzantine Empire. The wall stands far out in the countryside, roughly sixty-five kilometres west of the old city. It was built as an outer shield, a first barrier that an enemy army met long before it reached the famous walls of the capital.

The idea was simple, and it was bold. The wall ran across the whole Thracian peninsula, from the Black Sea in the north to the Sea of Marmara in the south. Its length is usually given as about fifty-six kilometres. Any army that marched toward Constantinople by land had to cross it. The wall also protected the farms, villas and water supply in the land behind it. People in the capital depended on those farms for food and on that water every day.

The wall takes its name from Emperor Anastasius the First, who ruled from 491 until 518. He was an older man and a careful administrator when he took the throne. He is remembered mainly for a full treasury, not for military glory. Some historians think the project started earlier, under one of his predecessors, and that Anastasius completed it or rebuilt it. In any case, his name stayed with the wall. Here is the first surprise: the man linked to this great military work is best known in the history books for his skill with money.

Why did the empire need such a barrier? The fifth and sixth centuries were dangerous for the Roman Balkans. Groups from beyond the Danube River, the old northern frontier, crossed into imperial land again and again. Huns, Goths, Bulgars and later Slavs and Avars came through. Each raid could reach the rich farmland near the capital. The wall was a way to close that open door with stone, and to keep raiders away from the city's gardens and storehouses.

Now look at what is left in front of you. Where the wall survives best, it is a thick stone barrier. It has a core of rubble and mortar, faced with squared blocks. In some places you can still see the line of the face, the joints between the stones, and the patches where blocks have fallen away. Elsewhere, the wall is only a mound under the trees. You can follow it because the ground runs too straight for a natural hill.

The best-preserved stretches lie in the forests toward the Black Sea end, in the northern part of what is now Istanbul province. Here the trees have protected the stone for centuries. In more open country further south, farmers and villagers reused the blocks for houses, walls and roads. That is the second surprise. Pieces of this imperial barrier probably sit today inside ordinary village buildings across the region. Nobody can easily point to them, but the old wall still lives on in the walls of the countryside.

A wall this long was very hard to keep. It needed soldiers along its whole length, and it needed constant repair. In the sixth century, Emperor Justinian created special officials to guard and command the Long Walls. That shows how seriously the state took the line. It also shows how much effort and money it cost. Not every writer of the time was impressed. Some contemporary historians argued that the wall gave a false sense of safety and that it was too long to defend well.

That criticism proved partly right. In the mid-sixth century, earthquakes damaged parts of the wall. Raiders from the north later crossed it during an invasion and came close to the capital. The old general Belisarius, famous for his campaigns in Italy and North Africa, was called back to drive them away. A barrier is only as strong as its weakest stretch. Across fifty-six kilometres of hills and valleys, there were many weak stretches.

By the seventh century, the empire faced new crises on almost every frontier. Money and soldiers grew scarce. The Long Walls were slowly abandoned as a working defence. The empire pulled back to the mighty walls of Constantinople itself, which held for centuries more. Out here, the forest returned. Roots pushed into the mortar. Leaves built up in layers. The great line across Thrace became a quiet ridge that only shepherds, woodcutters and later archaeologists paid attention to.

In modern times, researchers have surveyed and mapped the wall, and some stretches have been studied in detail. They have traced its route over hills and through valleys, and recorded the remains of towers and forts along the line. Even so, much of it still lies under vegetation, and many questions remain open. When you walk here, you are not visiting a polished monument. You are walking along a site that is still being understood.

Take a moment to think about the scale of the work. Every block was cut, carried and set by hand. Lime for the mortar had to be burned in kilns. Wood had to be cut for scaffolding. Thousands of workers must have lived and worked in camps along this line. Imagine the noise of hammers and carts, the smoke of fires, and the orders called across the valleys. Today, the only sounds are birds, wind, and perhaps a tractor in a distant field.

As you stand here, look along the line of stone. Notice how the wall follows the ground, climbing slopes and dipping into hollows. Notice the colour of the mortar, pale and rough, still holding after fifteen centuries. Touch the stone if it is safe, and feel how cool it is in the shade. When you walk away, look back once. The wall will almost disappear into the trees again, a long grey line that once marked the edge of an empire.