Innovation No. 32 of 77 in the book

The Concentric Fortress

Monuments of defensive engineering along the Nile cataracts

When

c. 1870 BCE

Dynasty

12th Dynasty

Era

Middle Kingdom

In the Middle Kingdom, pharaoh Senusret I established the massive fortress of Buhen on the Nubian frontier, pioneering a defensive network his successors expanded south.

Its designers used defenses armies wouldn’t rediscover for millennia: a moat, a double line of walls, projecting towers to fire along the base, drawbridges and arrow slits angled for crossfire.

It is essentially the medieval concentric castle — layer inside layer — built 3,000 years before the Crusades.

The blueprint of the great stone castle was first drawn on the Nile.

The layout was documented by the British archaeologist Walter Emery in digs through the 1950s and 1960s, shortly before the site disappeared under the rising water of Lake Nasser. The excavation exposed a fortified complex of more than 13,000 square metres, preserved in unusual detail beneath the desert sand — which is why the plan can still be read despite the fortress itself now being submerged.

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