The Catholic kings finish conquering the last bastion of Muslims in Iberia, and immediately next they tell all Muslims and Jews to either convert to Christianity or to flee the peninsula, because they aren't going to like what's planned for them next. A very different ruler in Europe welcomed them, however:
Basically, the Turks managed to help Constantinople regain some of the economic importance it had gained during the centuries of collapse of the Byzantine Empire because they welcomed Jewish artisans that had been kicked out of Iberia.