Marranos regularly left the Peninsula clandestinely, or secured permission to take business trips abroad from which they never returned. There are even cases of their leaving for the ostensible purpose of making a pilgrimage to Rome. Once the authorities became aware of such stratagems they tried to intercept Marranos as they moved through Europe to places where they could practice Judaism openly. Furtively and openly, in trickles and in torrents, thousands of Marranos left the Iberian Peninsula during the nearly three and a half centuries of the Inquisition's power. The Marranos did not arrive to Amsterdam until around 1590, some 11 years after the Union of Utrecht (1579) and the birth of the United Provinces of the Netherlands as a Protestant state. Here too they had to wait until 1615 before Jewish settlement was officially authorized, but the Marranos in Amsterdam differed from those in other Protestant countries in that they openly practiced Judaism almost from the moment of their arrival. Thanks to the Marranos, Amsterdam became one of the greatest Jewish centers in the world in the 17th century; it had some of the finest academies and produced some of the greatest Jewish thinkers. For these persecuted returning Jews was this beautiful prayerbook produced.