Vikings in Iberia
Vikings returned to Galicia in 859, beginning what seems to have been a three-year campaign, during the reign of Ordoño I of Asturias. The main source for these events are Arabic histories compiled by Ibn Ḥayyān in the eleventh century, though some near-contemporary Latin sources also mention the events, and later Latin sources offer more elaborate, but less reliable, accounts. In the assessment of Ann Christys, what can be known about the Viking raids on Iberia in 859-61 is thatThe expedition of 859–861, like that of 844, seems to have involved a single band of adventurers. Returning to the scene of Viking incursions in northern Iberia and al-Andalus, but meeting with little success, they sailed on to raid targets on the shores of the Mediterranean. Here they may have taken captives for ransom or to trade as slaves. Vikings seem to have over-wintered in Francia, perhaps waiting on the northern shore of the Mediterranean for favourable tides and currents to exit the sea through the Straits of Gibraltar. They may even have sailed to Italy, Alexandria and Constantinople.Some historians have given credence, however, to a range of accounts in late sources about raids in this period as evidence for this Viking incursion. Yet different sources mention different figures; not all potentially relevant raids recounted were necessarily by Vikings; and the sources are likely more to reflect the political context in which they were composed than actual events in 859-61. For example, on the basis of an account by Al-Bakrī it has been supposed that in 859 or 860, Vikings sailed through Gibraltar and raided the little Moroccan state of Nekor, and defeated a Moorish army. But there is no evidence that the raiders in question were Vikings. Likewise, the raiders have been identified as the legendary Hastein and Björn Ironside, but this is based on modern extrapolation from already altogether unreliable medieval sources. There was a well-attested raid on Constantinople in 860, which may have been by Vikings and which has been associated with the raids on Iberia, but there is no evidence that the raid on Constantinople was by the same people who were active in the western Mediterranean at the time. Moreover, it is plausible that the Constantinople raiders came from the north by the river-routes running from the Baltic into the Black Sea (known in Old Norse as the "Austrvegr"). A story about an attack in the period 859-61 on "Banbalūna" (which could mean modern Pamplona but also the whole kingdom of Navarre), again, may or may not reflect activities of Vikings.
Denmark
From the 8th to the 10th century the wider Scandinavian region was the source of Vikings. They colonised, raided, and traded in all parts of Europe. The Danish Vikings were most active in the eastern and southern British Isles and Western Europe. They conquered and settled parts of England (known as the Danelaw) under King Sweyn Forkbeard in 1013, and France where Danes and Norwegians founded Normandy with Rollo as head of state. More Anglo-Saxon pence of this period have been found in Denmark than in England.
Denmark was largely consolidated by the late 8th century and its rulers are consistently referred to in Frankish sources as kings ("reges"). Under the reign of Gudfred in 804 the Danish kingdom may have included all the lands of Jutland, Scania and the Danish islands, excluding Bornholm.
The extant Danish monarchy traces its roots back to Gorm the Old, who established his reign in the early 10th century. As attested by the Jelling stones, the Danes were Christianised around 965 by Harald Bluetooth, the son of Gorm. It is believed that Denmark became Christian for political reasons so as not to get invaded by the rising Christian power in Europe, the Holy Roman Empire, which was an important trading area for the Danes. In that case, Harald built six fortresses around Denmark called Trelleborg and built a further Danevirke. In the early 11th century, Canute the Great won and united Denmark, England, and Norway for almost 30 years with a Scandinavian army.