What is now Scotland was populated by various tribes in the days of the Roman Empire and before. These tribes included the Picts, the Scots, the Gododdin, and others. Early kingdoms included Dalriada, Galloway, Lothian, Rheged, and Strathclyde.

Many historians consider Kenneth mac Alpin to be the first official king of Scotland. The King of Dalriada and the grandson of a Pict, Kenneth had a military and a genetic claim to being ruler of both. He made it official by conquest in 843. He came to be known as The Conqueror, and the kingdom he founded came to be called the Kingdom of Alba. His reign was punctuated by raids from ravaging Norsemen.

When Kenneth mac Alpin died of natural causes in 858, his brother became King Donald I (also called Domnall). This king ruled only four years and died of natural causes. Constantine I, thought to have been a king of Kenneth mac Alpin, took the throne in 862. His reign was populated by a number of Viking invasions, and he died so defending his realm in 878. His brother Aedh succeeded him but ruled only a year and was succeeded by a grandson of Kenneth, Eochaid, who ruled for a decade and was then deposed by Donald II, a son of Constantine I and the first monarch to be termed King of Scotland.

Donald II ruled 11 years and was killed in battle. Next on the throne was Aedh's son Constantine II. This king invaded Northumbria but couldn't keep it, instead submitting to the Saxon king Edward the Elder. After another defeat in 942, this one at the hands of Edward's son Æthelstan, Donald handed over the throne to his cousin, who became Malcolm I, whose father was Donald II.

Kenneth III ruled from 997 to 1005. He was killed in battle by Malcolm II. This king made an alliance with King Owen the Bald of Strathclyde, and the joint force defeated England's King Canute at the Battle of Carham in 1018. Malcolm claimed Strathclyde for his grandson, Duncan, when Owen died; this alienated enough of of Malcolm's enemies that he was murdered in 1034.

Duncan I succeeded his grandfather and was killed in battle by Macbeth in 1040, who ruled for 17 years. Macbeth lost twice in battle to Duncan's son Malcolm; in the latter battle, Macbeth lost his life. His stepson, Lulach, became king and ruled for a year. He was killed in battle by Malcolm, who became King Malcolm III.

This Malcolm, who became known as Malcolm Canmore, was on the Scottish throne at the time of the Norman Conquest. He had taken the throne from Macbeth in 1057. When William the Conqueror invaded Scotland, he was successful enough that he forced Malcolm to submit to vassalage, resulting in the Peace of Abernethy in 1272. Malcolm married Margaret of Wessex, a grand-niece of English King Edward the Confessor. Malcolm invaded Northumbria in 1280, but a smart response from William's forces convinced the Scottish king to agree to keep the peace. Malcolm was not as deferential to William's successor, William Rufus, invading Northumbria yet again and causing a great amount of damage. He was killed in the first Battle of Alnwick in November 1093.

Macbeth had taken the throne in 1040 after defeating King Duncan I in battle. A son of Duncan, Donald III Bane, took the throne after his brother, Malcolm III, died. This king's reign was short because he was unseated by his nephew, Duncan II, who took revenge on his uncle in 1094 for being sent to the court of William the Conqueror as a hostage. In claiming the throne recently vacated by his father, Duncan II had help from England's King William Rufus. Turnabout being fair play, as the saying goes, Donald III Bane regained the throne a year after losing it by arranging the murder of his usurping nephew.

In his second stint as king, Donald III Bane was on the throne for three years before being brushed aside by another nephew, Edgar. Again with help from the English king William Rufus, Edgar seized the throne. Edgar's sister Edith married England's King Henry I in 1100.

Edgar died in 1107. Succeeding him was his brother, Alexander I. Alexander married a daughter of Henry I but died childless in 1124, giving way to his brother, David I, the Prince of the Cumbrians and Malcolm Canmore's youngest son. David A powerful, expansion-minded king, David rivaled the English Crown for influence at this time. He invaded England three times and won significant concessions from England's King Stephen. He was a patron of the church, founding more than a dozen abbeys. The first Scottish king to mint his own coins, he anticipated the rise of feudalism and founded more than a dozen burghs, or towns. He saw to it that his grandson was named heir to the throne. When David I died, his grandson became King Malcolm IV. It was this king who had run-ins with the English Henry II and surrendered lands that his predecessor had gained. Malcolm died unmarried and childless and was succeeded by his brother, William, who became known as William the Lion.

William, who took the throne in 1165, set about invading northern England but didn't manage to keep it. Instead, he was defeated at the second Battle of Alnwick and captured by Henry II, who demanded a high price from the Scottish nobles for their king's release: oaths of allegiance and the surrender of their sons as hostages. Henry sent English garrisons into Scotland as well. William ruled for several decades, gaining Scottish independence in 1189 in exchange for a large sum of money finding its way into the English Crown's coffers.

William's son Alexander II became king in 1214. Alexander and England's King Henry III established the Anglo-Scottish agreement in 1217. Alexander gave up any further claim to Northumbria and married Henry's sister Joan, in 1221.

Alexander II died in 1249 and was succeeded by his son, who became Alexander III. This King Alexander married Margaret, the daughter of England's King Henry III, in 1251. Alexander and Margaret had two sons, both of whom died young. Alexander, conscious of needing an heir, convinced his nobles to declare his granddaughter Margaret as the heir to the throne. She was 3 when her grandfather died in 1286.

Margaret, known as the Maid of Norway, was technically the ruler of Scotland but never sat on the throne. She was en route when she died. Her death in 1290 touched off a succession controversy known as the Great Cause.