Al-Roumi, makes a good point about banking. However, this is tied very closely into ideology and social status. The strong muslim influence in Spain was apparent also in that earning interest on money (what banking is based on) was considered usury, and therefore menial labour unsuitable for an hidalgo. Since in Spain, at the time, and for a very long time after, considering someone NOT to be an hidalgo was grounds for a duel to the death, and 'cleanliness of blood' (funny concept that basically implied proving that all your ancestors as far as records exist were not descendants of muslims or jews - which gave rise to a mafia running falsifications of birth certificates, and family trees, as 'cleanliness' was a requirement for public office or any meaningful job within the government. Only hidalgos were allowed to carry swords,for example. To keep their status they couldnt engage in usury, or do manual labour. Obviously that didn't help the economy...