Evidence indicating that Anglo-Saxons occupied Dublin before the Vikings arrived in 841 has been discovered in an archaeological dig at Copper Alley in Temple Bar West.
The dig uncovered a "strange house" predating the Vikings' arrival, which is believed to be Anglo-Saxon.
The director of the dig, Ms Linzi Simpson, told The Irish Times the find was "very exciting". While working on a Viking dig they knew immediately the house was not Scandinavian, and a comb found in it could only have come from Roman-Britain.
The house was also found at the very lowest level, under Viking buildings. These three factors convinced them of habitation in the area before the Vikings arrived. English archaeologists who came to look at the house had said "they had found hundreds of those in England", Ms Simpson said.
The excavation, which took place between 1996-1998, found that the Vikings had come up the river but other people were there when they arrived, she said.
The "house" was very clear and was seven metres by four metres, with a hearth, a side entrance and a type of wall which Viking buildings did not have. It was "quite extraordinary", said Ms Simpson, and showed there was Anglo-Saxon involvement in Irish affairs from an early stage.
The excavation has also yielded a remarkable and uninterrupted sequence of Viking habitation from the 9th century to the collapse of Viking Dublin in the late 12th century.
Other finds included dress jewellery, an intricate gold panel, dress pins, finger rings, amber pendants, everyday objects such as knives, sharpening stones, hammers, timber bowls and spoons, wattle dwellings, a human skeleton and animal bones from pigs, goats, dogs and cats.
The findings are detailed in a book by Ms Simpson entitled Temple Bar West - Director's Findings, which was launched yesterday by the Minister for the Environment, Mr Dempsey. The excavation has been documented by RTE in a film to be screened next Tuesday.
The director of Ireland's National Museum, Dr Patrick Wallace, hailed the new report as very significant. "The really important thing is the comparatively early date established by these findings," he said. "We now know that there was urban life in the proper sense in Dublin before 900."
The excavation was undertaken for Temple Bar Properties. The site is now the location of a large development known as the Old City, comprising 190 apartments and retail space.