Baruch Spinoza was a Dutch philosopher of Sephardi Portuguese origin. The breadth and importance of Spinoza's work was not fully realized until many years after his death. By laying the groundwork for the 18th-century Enlightenment and modern biblical criticism, including modern conceptions of the self and, arguably, the universe, he came to be considered one of the great rationalists of 17th-century philosophy. His magnum opus, the posthumous Ethics, in which he opposed Descartes' mind–body dualism, has earned him recognition as one of Western philosophy's most important thinkers. In the Ethics, "Spinoza wrote the last indisputable Latin masterpiece, and one in which the refined conceptions of medieval philosophy are finally turned against themselves and destroyed entirely." Hegel said, "You are either a Spinozist or not a philosopher at all." His philosophical accomplishments and moral character prompted 20th-century philosopher Gilles Deleuze to name him "the 'prince' of philosophers".Spinoza's given name varies between different languages: Baruch Spinoza, and ; in all these languages, the given name means "Blessed". Spinoza was raised in the Portuguese Jewish community in Amsterdam. He developed highly controversial ideas regarding the authenticity of the Hebrew Bible and the nature of the Divine. The Jewish religious authorities issued a cherem against him, effectively excluding him from Jewish society at age 23. His books were also later put on the Catholic Church's Index of Forbidden Books.