Scotland in the Middle Ages concerns the history of Scotland from the departure of the Romans to the adoption of major aspects of the Renaissance in the early sixteenth century. From the fifth century northern Britain was divided into a series of kingdoms. Of these the four most important to emerge were the Picts, the Gaels of Dál Riata, the Britons of Strathclyde and the Anglo-Saxon kingdom of Bernicia, later taken over by Northumbria. After the arrival of the Vikings in the late eighth century, Scandinavian rulers and colonies were established along parts of the coasts and in the islands. In the ninth century the Scots and Picts combined under the House of Alpin to form a single Kingdom of Alba, with a Pictish base and dominated by Gaelic culture. After the reign of King David I in the twelfth century, the Scottish monarchs are best described as Scoto-Norman, preferring French culture to native Scottish culture. Alexander II and his son Alexander III, were able to regain the remainder of the western seaboard, cumulating the Treaty of Perth with Norway in 1266. After being invaded and briefly occupied, Scotland re-established its independence from England under figures including William Wallace in the late thirteenth century and Robert Bruce in the fourteenth century. In the fifteenth century under the Stewart Dynasty, despite a turbulent political history, the crown gained greater political control at the expense of independent lords and regained most of its lost territory to approximately the modern borders of the country. However, the Auld Alliance with France led to the heavy defeat of a Scottish army at the Battle of Flodden in 1513 and the death of the king James IV, which would be followed by a long minority and a period of political instability. Kingship was the major form of government, growing in sophistication in the late Middle Ages. The scale and nature of war also changed, with larger armies, naval forces and the development of artillery and fortifications. The Church in Scotland always accepted papal authority (contrary to the implications of Celtic Christianity), introduced monasticism, and from the eleventh century embraced monastic reform, developing a flourishing religious culture that asserted its independence from English control. Scotland grew from its base in the eastern Lowlands, to approximately its modern borders. The varied and dramatic geography of the land provided a protection against invasion, but limited central control. It also