Bueno family. Joseph Bueno was consulted in the illness of Prince Maurice in April, 1623. Jews were admitted as students to the university, where they studied medicine as the only branch of science that was of practical use to them. They were not allowed to practice law, because lawyers were required to take a Christian oath, thereby excluding them. Jews were also excluded from the trade guilds, as in a 1632 resolution passed by the city of Amsterdam (the Dutch cities were largely autonomous). However, they were allowed to practice certain trades: printing, bookselling, and selling meat, poultry, groceries, and medicines. In 1655 a Sephardic Jew was exceptionally permitted to establish a sugar refinery using chemical methods. Several Sephardic Jews stood out during that time, including Menasseh Ben Israel. He was known for corresponding widely with Christian leaders and helped to promote Jewish resettlement in England. Perhaps the most famous among Dutch Jews of Sephardic origin is Benedictus de Spinoza (Baruch Spinoza), a philosopher, scholar and optician who was excommunicated from the Jewish community in 1656 after speaking out his ideas concerning (the nature of) God, later published in his famous work Ethics Demonstrated in Geometrical Order (1677). Ashkenazim Many German Jews were also attracted later to the tolerant and independent Dutch provinces, generally after the mid-17th century, whichof one example could be the Haham Tzvi. Unlike the more acculturated Iberian Jews, most of these were displaced residents of Jewish ghettos escaping persecution. In addition they were displaced by the violence of the Thirty Year War (1618–1648) in other parts of northern Europe, and local expulsions, as well as the 1648 Khmelnytsky uprising in what was then eastern Poland. These poor immigrants were less welcomed. Their arrival in considerable number threatened the economic status of Amsterdam in particular, and with few exceptions they were turned away. They generally settled in rural areas, where they subsisted typically as peddlers and hawkers. Many smaller Jewish communities were started throughout the Dutch provinces. Over time, many German Jews gained prosperity through retail trading and they became specialists in diamond-cutting and sales. They had a monopoly in the latter trade until about 1870. When William IV was proclaimed stadholder (1747), the Jews found another protector. He had close relations with the head of the DePinto family, at whose villa, Tulpenburg, near Ouderkerk, he and his wife paid more than one visit. In 1748, when