<P> Around 141, the Romans undertook a reoccupation of southern Scotland, moving up to construct a new limes between the Firth of Forth and the Firth of Clyde, which became the Antonine Wall . The largest Roman construction inside Scotland, it is a sward - covered wall made of turf around 20 feet (6 m) high, with nineteen forts . It extended for 37 miles (60 km). Having taken twelve years to build, the wall was overrun and abandoned soon after 160 . The Romans retreated to the line of Hadrian's Wall . Roman troops penetrated far into the north of modern Scotland several more times, with at least four major campaigns . The most notable invasion was in 209 when the emperor Septimius Severus led a major force north . After the death of Severus in 210 they withdrew south to Hadrian's Wall, which would be Roman frontier until it collapsed in the 5th century . By the close of the Roman occupation of southern and central Britain in the 5th century, the Picts had emerged as the dominant force in northern Scotland, with the various Brythonic tribes the Romans had first encountered there occupying the southern half of the country . Roman influence on Scottish culture and history was not enduring . </P> <P> In the centuries after the departure of the Romans from Britain, there were four groups within the borders of what is now Scotland . In the east were the Picts, with kingdoms between the river Forth and Shetland . In the late 6th century the dominant force was the Kingdom of Fortriu, whose lands were centred on Strathearn and Menteith and who raided along the eastern coast into modern England . In the west were the Gaelic (Goidelic) - speaking people of Dál Riata with their royal fortress at Dunadd in Argyll, with close links with the island of Ireland, from whom comes the name Scots . In the south was the British (Brythonic) Kingdom of Strathclyde, descendants of the peoples of the Roman influenced kingdoms of "Hen Ogledd" (Old north), often named Alt Clut, the Brythonic name for their capital at Dumbarton Rock . Finally, there were the English or "Angles", Germanic invaders who had overrun much of southern Britain and held the Kingdom of Bernicia, in the south - east . The first English king in the historical record is Ida, who is said to have obtained the throne and the kingdom about 547 . Ida's grandson, Æthelfrith, united his kingdom with Deira to the south to form Northumbria around the year 604 . There were changes of dynasty, and the kingdom was divided, but it was re-united under Æthelfrith's son Oswald (r . 634 - 42). </P> <P> Scotland was largely converted to Christianity by Irish - Scots missions associated with figures such as St Columba, from the fifth to the seventh centuries . These missions tended to found monastic institutions and collegiate churches that served large areas . Partly as a result of these factors, some scholars have identified a distinctive form of Celtic Christianity, in which abbots were more significant than bishops, attitudes to clerical celibacy were more relaxed and there was some significant differences in practice with Roman Christianity, particularly the form of tonsure and the method of calculating Easter, although most of these issues had been resolved by the mid-7th century . </P> <P> Conversion to Christianity may have speeded a long term process of gaelicisation of the Pictish kingdoms, which adopted Gaelic language and customs . There was also a merger of the Gaelic and Pictish crowns, although historians debate whether it was a Pictish takeover of Dál Riata, or the other way around . This culminated in the rise of Cínaed mac Ailpín (Kenneth MacAlpin) in the 840s, which brought to power the House of Alpin . In 867 AD the Vikings seized the southern half of Northumbria, forming the Kingdom of York; three years later they stormed the Britons' fortress of Dumbarton and subsequently conquered much of England except for a reduced Kingdom of Wessex, leaving the new combined Pictish and Gaelic kingdom almost encircled . When he died as king of the combined kingdom in 900, Domnall II (Donald II) was the first man to be called rí Alban (i.e. King of Alba). The term Scotia was increasingly used to describe the kingdom between North of the Forth and Clyde and eventually the entire area controlled by its kings was referred to as Scotland . </P>

When did scotland win its freedom from england