Jews arriving in the Ottoman Empire were mostly resettled in and around Thessalonica and to some extent in Constantinople and İzmir. This was followed by a great massacre of Jews in the city of Lisbon in 1506 and the establishment of the Portuguese Inquisition in 1536. This caused the flight of the Portuguese Jewish community, which continued until the extinction of the Courts of Inquisition in 1821; by then there were very few Jews in Portugal. In Amsterdam, where Jews were especially prominent in the 17th century on account of their number, wealth, education, and influence, they established poetical academies after Spanish models; two of these were the "Academia de los Sitibundos" and the "Academia de los Floridos". In the same city they also organized the first Jewish educational institution, with graduate classes in which, in addition to Talmudic studies, instruction was given in the Hebrew language. The most important synagogue, or Esnoga, as it is usually called amongst Spanish and Portuguese Jews, is the Amsterdam Esnoga—usually considered the "mother synagogue", and the historical centre of the Amsterdam minhag. A sizable Sephardic community had settled in Morocco and other Northern African countries, which were colonized by France in the 19th century. Jews in Algeria were given French citizenship in 1870 by the "décret Crémieux" (previously Jews and Muslims could apply for French citizenship, but had to renounce the use of traditional religious courts and laws, which many did not want to do). When France withdrew from Algeria in 1962, the local Jewish communities largely relocated to France. There are some tensions between some of those communities and the earlier French Jewish population (who were mostly Ashkenazi Jews), and with Arabic-Muslim communities. The largest part of Spanish Jews expelled in 1492 fled to Portugal, where they eluded persecution for a few years. The Jewish community in Portugal was perhaps then some 15% of that country's population. They were declared Christians by Royal decree unless they left, but the King hindered their departure, needing their artisanship and working population for Portugal's overseas enterprises and territories. Later Sephardic Jews settled in many trade areas controlled by the Empire of Philip II and others. With various countries in Europe also the Sephardi Jews established commercial relations. In a letter dated 25 November 1622, King Christian IV of Denmark invites Jews of Amsterdam to settle in Glückstadt, where, among other privileges, the free exercise of their religion would be assured to them.  Álvaro Caminha, in Cape Verde islands, who received the land as a grant from the crown, established a colony with Jews forced to stay on the island of São Tomé.