The first mention of Belfast in the history of Ireland was in 666 AD when the Cruithin and Ulaid tribes clashed in a battle at the ford. The Ulaid were the tribe after which Ulster gained its name; the Cruithin were a Pictish tribe. There is, however, evidence of earlier occupation in the area circa 7000 BC; as the Ice Age retreated there is evidence that Mesolithic people collected cockles from the mud banks of the River Lagan. High on a hillside overlooking what today is the Shaw's Bridge area sits the Giant's Ring and Neolithic dolmen which dates from 3000 BC. The Celts are believed to have first named the place B al F irste in about 500 BC.

Around about 900 AD Vikings were present all along Belfast Lough giving the name of some of the settlements along the shoreline, including Ballyholme, their names in Old Norse. The Vikings who settled at Belfast also worked on shallow boats on the banks of the Lagan, probably beating Harland and Wolff [Belfast's famous ship-building company. ] to the Queen's Island site by over a millennium. From the sheltered harbours on the Irish coast the Vikings launched attacks on