On an exposed cliff top overlooking the North Sea, the Picts built a fortress to defend themselves from invading Scots, Saxons, and Britons. Over succeeding years this fortress was to grow in importance because of its strategic location at the mouth of the River Forth.

Sometime between the years of 835 A.D. and 839 A.D., after the Battle of Scone, when Dursken, King of the Picts was slain and his followers fled, this fortress was awarded by Kenneth I, King of Scotland to a brave and valiant captain of the Scots named Bar. Thus the fortress became known in the Gaelic as Dun Bar, or the Tower or Fortress of Bar on the Hill. The first person to use the name of Dunbar was Gospatric I ,who rebuilt the wood and wattle Tower of Bar into the stone castle that was to become the home of one of the most powerful families in Scotland.

The Dunbar Earls of Dunbar and March controlled much of Lothian, and all of "The Borders", Berwick, Peebles, Selkirk and Roxburgh, plus great holdings in Northumberland and Cumberland. Through marriage to the famous "Black" Agnes Randolph, the Dunbar Earls acquired the Earldom of Moray as well, holding Aberdeenshire, Morayshire, Nairn, Buchan, and Inverness.

While the Privy Council of Scotland recognized the Dunbars as a clan in 1579, the House of Dunbar has always been infinitely more than a clan. As a famous 17th century historian remarked, " Second only to the Cummings, and of course, the Royal family, the Dunbars are the greatest family of Scotland". Sir Robert Douglas noted, "No name in Scotland can boast of a more noble name than Dunbar". In Gospatric, First Earl of Dunbar and founder of this great family, the greatest families of Scotland, Pictland, Northumbria, and England were combined to prove Douglas' evaluation.