To understand the rise and fall of empires, one must always look as much at the forces and circumstances of the home country as at conditions in the field. When the Portuguese conquered the South Atlantic, they were in the van of navigational technique. A readiness to learn from foreign savants, many of them Jewish, had brought knowledge that translated directly into application; and when, in 1492, the Spanish decided to compel their Jews to profess Christianity or leave, many found refuge in Portugal, then more relaxed in its anti-Jewish sentiments. But in 1497, pressure from the roman Church and Spain led the Portuguese crown to abandon this tolerance. Some seventy thousand Jews were forced into a bogus but nevertheless sacramentally valid baptism. In 1506, Lisbon saw its for pogrom, which left two thousand “converted” Jews dead. (Spain had benn doing as much for two hundred years.) From then on, the intellectual and scientific life of Portugal descended into an abyss of bigotry, fanaticism, and purity of blood.
The descent was gradual. The Portuguese Inquisition was installed only in the 1540’s and burned its first heretic in 1543; but it did not become grimly unrelenting until the 1580’s, after the union of the Portuguese and Spanish crowns in the person of Phillip II. In the meantime, the crypto-Jews, including Abraham Zacut and other astronomers, found life in Portugal dangerous enough to leave in droves. They took with them money, commercial know-how, connections, knowledge, and – even more serious – those immeasurable qualities of curiosity and dissent that are the leaven of thought.
That was a loss, but in matters of intolerance, the persecutor’s greatest loss is self-inflicted. It is this process of self-diminution that gives persecution its durability, that makes it, not the event of the moment, or of the reign, but of lifetimes and centuries. By 1513, Portugal wanted for astronomers; by the 1520’s, scientific leadership had gone. The country tried to create a new Christian astronomical and mathematical tradition but failed, not least because good astronomers found themselves suspected of Judaism.
As in Spain, the Portuguese did their best to close themselves off from foregin and heretical influences. Education was controlled by the Church, which maintained a medieval curriculum focused on grammar, rhetoric, and scholastic argument. Featured were exhibitionism and hair-splitting (some 247 rhymed, learn-by-heart rules on the syntax of Latin nouns). The only science at the higher level was to be found in the one faculty of medicine at Coimbra. Even there, few instructors were ready to abandon Galen for Harvey or teach the yet more dangerous ideas of Copernicus, Galileo, and Newton, all banned by the Jesuits as late as 1746.