A.D. 400. Settlers from the Irish petty kingdom of Dál Riata were beginning to establishing themselves in what would later be called Scotland. Picts were well established north of other Celtic speakers except perhaps on the west coast and in the Hebrides.
A.D. 500. Departure of Roman legions in A.D. 407 left Britain to Picts, other Celtic speakers, and growing numbers of Irish settlers. Enough Scotti were in place by A.D. 490 to allow them to move the seat of Dál Riata from across the Irish Sea.
A.D. 600. Colum Cille left Ireland and established a monastery on Iona in 563. From this time on expansion of the Irish Scotti was assisted in part by the spread of Christianity.
A.D. 700. As the Scottish presence in Britain grew, so did that of the Angles and Saxons, many the descendants of Roman mercenaries. Angle settlements expanded south and east of Scottish territory.
A.D. 800. As both Angle and Scottish communities grew, small Norse settlements began to appear in the islands of Orkney and the Outer Hebrides.
A.D. 900. Competition from the Norse and Angles probably contributed to the unification of Scots and Picts into a single kingdom in 844. Pictish language and culture disappeared. Norse raids forced the abandonment of Iona by 878.
A.D. 1000. By 1,000 years ago the Picts were a memory and the united kingdom of Scotland was caught between Germanic Norse and Angle settlers.