Spinoza's magnum opus, Ethics, was published posthumously in 1677. The work opposed Descartes' philosophy on mind–body dualism, and earned Spinoza 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". Georg Wilhelm Friedrich Hegel said, "The fact is that Spinoza is made a testing-point in modern philosophy, so that it may really be said: You are either a Spinozist or not a philosopher at all." His philosophical accomplishments and moral character prompted Gilles Deleuze to name him "the 'prince' of philosophers."
Spinoza was raised in a Portuguese Jewish community in Amsterdam. He developed highly controversial ideas regarding the authenticity of the Hebrew Bible and the nature of the Divine. Jewish religious authorities issued a herem (חרם) against him, causing him to be effectively shunned by Jewish society at age 23. His books were also later put on the Catholic Church's Index of Forbidden Books.
Spinoza lived an outwardly simple life as a lens grinder, turning down rewards and honours throughout his life, including prestigious teaching positions. He died at the age of 44 allegedly of a lung illness, perhaps tuberculosis or silicosis exacerbated by the inhalation of fine glass dust while grinding optical lenses. He is buried in the churchyard of the Christian Nieuwe Kerk in The Hague.
Spinoza's ancestors were of Sephardic Jewish descent and were a part of the community of Portuguese Jews that had settled in the city of Amsterdam in the wake of the Portuguese Inquisition (1536), which had resulted in forced conversions and expulsions from the Iberian peninsula.
Although the Portuguese name "de Espinosa" or "Espinosa," then spelled with a "z," can be confused with the Spanish "de Espinoza" or "Espinoza," there is no evidence in Spinoza's genealogy that his family came from Espinosa de los Monteros, near Burgos, or from Espinosa de Cerrato, near Palencia, both in Northern Castile, Spain. Still, this was a common Portuguese conversos family name.