Viking and Gaelic Irish settlement into south-west Scotland produced the Gall-Gaidel, the Norse Irish, from which the region gets the modern name Galloway. Sometime in the ninth century the beleaguered Kingdom of Dál Riata lost the Hebrides to the Vikings, when Ketil Flatnose is said to have founded the Kingdom of the Isles. These threats 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 AD 867 the Vikings seized 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 would be increasingly be used to describe the kingdom between North of the Forth and Clyde and eventually the entire area controlled by its kings would be referred to as Scotland. High Middle Ages Gaelic kings: Constantine II to Alexander I The long reign (900–942/3) of Causantín (Constantine II) is often regarded as the key to formation of the Kingdom of Alba. He was later credited with bringing Scottish Christianity into conformity with the Catholic Church. After fighting many battles, his defeat at Brunanburh was followed by his retirement as a Culdee monk at St. Andrews. The period between the accession of his successor Máel Coluim I (Malcolm I) and Máel Coluim mac Cináeda (Malcolm II) was marked by good relations with the Wessex rulers of England, intense internal dynastic disunity and relatively successful expansionary policies. In 945, Máel Coluim I annexed Strathclyde, where the kings of Alba had probably exercised some authority since the later ninth century, as part of an agreement with King Edmund of England. This event was offset by loss of control in Moray. The reign of King Donnchad I (Duncan I) from 1034 was marred by failed military adventures, and he was defeated and killed by