From Salonica, City of Ghosts: Christians, Muslims and Jews, 1430-1950, by Mark Mazower (Vintage, 2006), pp. 47-48:
WHEN THE ENGLISH expelled their Jews in 1290, they inaugurated a policy which spread widely over the next two centuries. In 1492 Ferdinand and Isabella’s edict of banishment forced thousands from a homeland where they had known great security and prosperity. Sicily and Sardinia, Navarre, Provence and Naples followed suit. By the mid-sixteenth century, Jews had been evicted from much of western Europe. A few existed on sufferance, while many others converted or went underground as Marranos and New Christians, preserving their customs behind a Catholic facade. The centre of gravity of the Jewish world shifted eastwards—to the safe havens of Poland and the Ottoman domains.
In Spain itself not everyone favoured the expulsions. (Perhaps this was why a different policy was chosen towards the far more numerous Muslims of Andalucia who were forcibly converted, and only expelled much later.) “Many were of the opinion,” wrote the scholar and Inquisitor Jeronimo de Zurita, “that the king was making a mistake to throw out of his realms people who were so industrious and hard-working, and so outstanding in his realms both in number and esteem as well as in dedication to making money.” A later generation of Inquisitors feared that the Jews who had been driven out “took with them the substance and wealth of these realms, transferring to our enemies the trade and commerce of which they are the proprietors not only in Europe but throughout the world.”
The expulsion of the Jews formed part of a bitter struggle for power between Islam and Catholicism. One might almost see this as the contest to reunify the Roman Empire between the two great monotheistic religions that had succeeded it: on the one side, the Spanish Catholic monarchs of the Holy Roman Empire; on the other, the Ottoman sultans, themselves heirs to the Roman Empire of the East, and rulers of the largest and most powerful Muslim empire in the world. Its climax, in the sixteenth century, pitted Charles V, possessor of the imperial throne of Germany and ruler of the Netherlands, the Austrian lands, the Spanish monarchy and its possessions in Sicily and Naples, Mexico and Peru, against Suleyman the Magnificent, who held undisputed sway from Hungary to Yemen, from Algiers to Baghdad. Ottoman forces had swept north to the gates of Vienna and conquered the Arab lands while Ottoman navies clashed with the Holy League in the Mediterranean and captured Rhodes, Cyprus and Tunis, wintered in Toulon, seized Nice and terrorized the Italian coast. The Habsburgs looked for an ally in Persia; the French and English approached the Porte. It was an early modern world war.