Area was inhabited by 3rd millenium BCE; Rome invaded, but never subdued native Picts; invaded by Scots from Ireland in the 6th century CE; Picts and Scots united in 844; invaded by Norsemen beginning in the 8th century; first linked with English monarchy in 12th century; 16th century marked by religious turmoil; Crowns of Scotland and England united in 1603, parliaments in 1707; significant percentage still read or speak Scottish Gaelic language.