A vast city containing up to 25 churches and the last ancient Egyptian- style temple and pyramid ever built, has been found some 500 miles south of the Mediterranean in what is now the Muslim republic of Sudan.
The kingdom flourished for almost 1000 years. Archaeologists estimate that its capital covered more than a square mile and could have had a population of 30,000. Its "cathedral" was a basilica-style 9th century church almost 30 yards long.
The Kingdom of Alwa existed as a Christian state from the late 6th century to the early 16th century and at its peak in 900 AD covered some 120,000 square miles, about the size of Italy.
It was one of four African Christian countries which once existed, cut off from the rest of Christendom by the Islamic world. Today the only survivor is Ethiopia, although some remnant communities lingered along the Middle Nile as late as the 18th century.
Alwa fell to Islam in 1504. The other lost kingdoms were Makuria and Dotawa. The populations were evangelised by missionaries sent from Roman-ruled Egypt prior to the Arab conquest of that country in 640 AD. They practised (as Ethiopia does today) a Christian rite inspired by the Egyptian Coptic church, which still flourishes.
The deserted remnants of Alwa's capital, Soba, were looted in the 19th century for bricks to build Khartoum, as were most of the kingdom's golden treasures. A 12-year excavation and research programme is about to be completed by the British Institute in Eastern Africa, which unearthed Soba's 2,000 sq yard palace and five large churches. Other major churches and public buildings have been tentatively identified.
Clues to the wealth of Soba include fragments of gold sheet and gold wire, pieces of gold thread, textiles, shards of fine Chinese porcelain and the marble tombstone of one of Alwa's early 11th century rulers, an African King David.
The excavations have revealed that the locally made Alwan pottery was extremely fine, often richly decorated with multi-coloured geometric designs and animal and human figures, including images of saints.
All the major ecclesiastical buildings of the city were made of fired rather than mud brick and were covered in whitewash. Internally the cathedral and other churches were decorated with magnificent wall paintings, tiny fragments of which have been unearthed.
As well as being the last of the Christian Kingdoms of the Nile Valley, Alwa was also in a way the last remnant of ancient Egyptian civilization itself. Most of ancient Egypt was taken over by the Romans in the 1st century BC, but an independent Egyptian-style kingdom known as Meroe persisted in southern Egypt and the Sudan until the 4th century AD. Alwa represented to all intents and purposes the continuation of Meroitic civilization.
Although for most of its existence it was Christian, before conversion the kingdom waspagan. Archaeologists have discovered what are probably the last Egyptian-style temple and the last pyramid (just five yards square) ever constructed. In 580 AD the temple was converted into a Christian church. A derivative of ancient Egyptian and Greek continued as the official languages.
"Our excavations have for the first time produced evidence of the importance of Alwa," said Dr Derek Welsby, the project's field director and Honorary Secretary of the British Museum-based Sudan Archaeological Research Society. "The finds suggest the late survival of ancient Egyptian traditions and show how a dynamic Christian culture flourished until the beginning of the 16th century along the Nile as far south as the central Sudan."