In 1993 archaeologists from the University of Edinburgh found the remains of eight Late Iron Age houses, dating back to AD 500 – 700, before the Viking Age began.
What they discovered is this early Scottish settlement eventually gave way to the Norse, probably as a popular trading hub. This excavation is the subject of a thesis by Jennifer E. Thoms, which can be read here: https://www.era.lib.ed.ac.uk/handle/1842/7283
http://www.medievalhistories.com/vikings-in-the-isle-of-lewis/