Apart from Muslim incursions, Spain was occupied by the Muslims for quite a long time. I thought when you said Crusade, you meant the Christian Crusades. Have you observed Spain didn't take part in any Crusade in the holy land? The reason was they they had the crusades in their own country to expell the occupyers.
High school teacher's union threatens strike (Haaretz)
from the article: Prison dig reveals church that may be the oldest in the world