The vikings invaded many lands including Spain which at the time was controlled by a Muslim Caliphate.
This is one of the more interesting of the Viking invasions as they did not care if their victims were Muslim or Christian.
The notorious son of Ragnar Lodbrok called Björn Ironside was one of the more successful of the Vikings to invade Spain.
While there is a lot of information missing there are several accounts placing the invasion around 859-861 AD.
The vikings were at first very successful in raiding Spain but as the defenses were built up they moved onto easier target in the Mediterranean such as Italy.
After filling their ships were loaded down with loot they notoriously ran into a trap at the Strait of Gibraltar by both Christians and Muslims.
Only 1 in 4 ships made it through the sea attack with Björn Ironside supposedly to have survived the battle.
All the viking who made it back home came back very rich which only led to more picking up their swords for more invasions.
It was not a surprise that the worshipers of Odin and Thor attacked the Christians, this was few years after Charlemagne had attacked the Saxons and chopped down Irminsul in 773. The German world tree, the one thing that, in their belief, held up the skies. The Scandinavian equivalent was Yggdrasil. It was an attack on the belief system, that was shared with the Scandinavians. They attacked Christianity and the heartland of it was France. The Viking age is heralded inn during Charlemagne’s reign. 793, the attack on Lindisfarne monastery. This started as a religious war for them, their belief was under attack and they retaliated, a monastery as the first victim. It was easy to get men when they could promise fat loot in addition.
The Saxon leader fled to Denmark after being defeated by Charlemagne in 776, i bet the stories he told at the Danish court shocked them to their foundations. For 30 years the Saxons fought the new religion, finally to accept it in 804. Charlemagne was on a crusade 300 years before the word was invented. He used religion as a means to control the new population, and military to subdue them. He came with new laws for the Saxons in 782, Capitulatio de partibus Saxoniae , that stated that any heathen that refuses to convert to Christianity must die, same if you hide among the Christians and conduct pagan rituals, you die, if you steal from a church or harm a priest, you die. This was the backdrop the Scandinavians where facing their world on in the late 700. It would take more than 200 years for Christianity to get a foothold in Norway after that.
Ireland and England had monastery’s hundreds of years before the attack on Lindisfarne, It was Christians in Norway way before that, why all of a sudden where the Christians under attack from former trading partners, now banned from christian markets. Its no mystery really. It was a northern rebellion of religions, retaliation, opportunity, power building and networking medieval style.
Wow, as a Zoroastrian myself, I found it interesting that the Spanish Muslims thought that the initial Norsemen raids were also carried out by “majus.” Good stuff!