Cologne - Archaeologists on Tuesday started one of the biggest projects ever undertaken in Europe, hoping to rewrite the 2 000-year history of Cologne.

The diggers have four years to shift 100 000 cubic metres of soil, looking for foundations and artefacts that will go on display at the city museum.

The Romans founded "Colonia" and it was one of European biggest cities in late Roman times and the Middle Ages. Past digs have yielded Roman mosaics, tombstones and oil lamps.

Chief archaeologist Hansgerd Hellenkemper said his team would try to discover why the Roman river port silted up and how Cologne was affected by a drastic change in the world's climate 1 800 years ago.

The team are to dig up to 13 metres under the surface at sites that have been reserved for an underground railway. When the 100 archaeologists leave, the engineers will move in. - Sapa-dpa