On April 4, 1609, the consejo de estado made a legal determination on the expulsion of Moriscos, and the total number of those expelled from the peninsula during four years to 1613 reached 9000,000. It was the letter of the end of 1601 from Don Juan Rivera, Archbishop of Valencia, that urged Felipe III to expell all Moriscos from Spain. Then the Spanish government anthorities made an entire amendment to their traditional policy of apeasement and adaptation of Moriscos which had lasted since their conquest over the kingdom of Granada. And they adopted a policy to exclude them as an outsider which is likely to spoil the national and religious integration of the nation. The sessions of Juntas and the high bishop congress which were often held since then, decided the enforcement of the order, rejecting even the earnest appeal of the aristocracy and cortes of Valencia where they had then the largest number of Moriscos. In this article it is tried to give a brief sketch of the circumstances which led to the expulsion order, and also to make a study, through the Vatican documents, on the attitudes it maintained in the matter and on the opinion which the Pope Paul V expressed when the official announcement of the order was made.