Not all Muslims invaded Spain either--it was mostly Berbers, new adherents to Islam. There were no Arabs in any number.
Regards,
Scott
Implying that the invation of Muslims for Spain was a slip or just a mere mistake is not apperciated. I advice you to read more about that period of history.
Spain was already under another foreign ruler whom the people of Spain were suffering from. Muslims didn't just stole that land out from it's people. That was not the case. Althought i wanted to use some islamic resources to prove that to you, because it's accurate and in details, but you would have doubt it. That's why i tried to use neutral resources.
The conquest
The traditional story is that in the year 711, an oppressed Christian chief, Julian, went to Musa ibn Nusair, the governor of North Africa, with a plea for help against the tyrannical Visigoth ruler of Spain, Roderick.
Musa responded by sending the young general Tariq bin Ziyad with an army of 7000 troops. The name Gibraltar is derived from Jabal At-Tariq which is Arabic for 'Rock of Tariq' named after the place where the Muslim army landed.
The story of the appeal for help is not universally accepted. There is no doubt that Tariq invaded Spain, but the reason for it may have more to do with the Muslim drive to enlarge their territory.
The Muslim army defeated the Visigoth army easily, and Roderick was killed in battle.
After the first victory, the Muslims conquered most of Spain and Portugal with little difficulty, and in fact with little opposition. By 720 Spain was largely under Muslim (or Moorish, as it was called) control.
Reasons
One reason for the rapid Muslim success was the generous surrender terms that they offered the people, which contrasted with the harsh conditions imposed by the previous Visigoth rulers.
The ruling Islamic forces were made up of different nationalities, and many of the forces were converts with uncertain motivation, so the establishment of a coherent Muslim state was not easy.
Andalusia
The heartland of Muslim rule was Southern Spain or Andulusia. The name Andalusia comes from the term Al-Andalus used by the Arabs, derived from the Vandals who had been settled in the region.
BBC - Religion & Ethics - Muslim Spain (711-1492): Conquest
As you can see, if it wasn't for Muslims, Christians and Jews would have remain under opression. Muslims set them free, which allowed the world to experince a period of enlightment which released europe from it's darkness and ignorance. These are plain facts in history.
All nations and all religions in europe should be gratful for what the Muslims did back then in Spain, if it wasn't for them, there would be no enlightment for europe at that critical period.
The Muslims were the first great religious force at that time who didn't use their force to convert people. They set them free from opression then gave them the chance to be exposed to Islam if they want, and then they have the choice whether to be Muslims or not. I can't count the massive books which was written by either Jews and Muslims, or Christians and Muslims scholars side by side. Therefore, if anyone is looking to hijack Islam, so i advice him to find another area than this one, because if one insisted to doubt what the Muslims did in Spain and how great they were, he will end up in absolute failure and total disappointment because all nations should be proud of what the Muslims did in Spain.