The Second Kushite Kingdom controlled the whole Nile valley from Khartoum to the Mediterranean from 720BC to 660BC.
Now archaeologists have discovered that a region of northern Sudan once considered a forgotten backwater once actually "a real power-base".
They discovered a ruined pyramid containing fine gold jewellery dating from about 700BC on a remote un-navigable 100-mile stretch of the Nile known as the Fourth Cataract, plus pottery from as far away as Turkey.
Other finds included numerous examples of ancient rock art and 'musical' rocks that were tapped to create a melodic sound.
They only made the discoveries after being invited by the Sudanese authorities to help excavate part of the Merowe region, which is soon to be flooded by a large hydro-electric dam. More than 10,000 sites were found.
Historians had written off the area as being of little archaeological interest.
Dr Derek Welsby, of the British Museum, said: "We had no idea how rich the area was."
Remarkably well-preserved bodies, naturally mummified in the desert air, and a cow buried complete with eye ointment were also unearthed.
Dr Welsby said the finds revolutionised the history and geography of the Kushite kingdoms.
The British Museum has been given 20 blocks of an ancient pyramid following an archaeological project that it said has transformed knowledge of ancient Sudan.
The London-based museum said Sudan let it keep the stones, which were among 390 granite pieces the dig located near the Nile's Fourth Cataract, which is now being flooded to provide hydroelectricity. The blocks made up an early Kushite structure dating between the 8th and 5th century B.C., the museum said in an e-mailed news release today.
Two rock gongs, which would have been played by striking them with quartzite pebbles, also have been given to the museum by Sudan. The pyramid blocks include examples of early art featuring camels, sheep and cows.