Modern Judaism is divided into several fractions whose appearance and values ​​are very different. While this has become the accepted standard in Judaism, this was not always the case. Freedom of religious thought in Judaism was considered evil, and the preaching of these ideas could lead to excommunication from the community. This was the fate of one of the most important 17th century philosophers in the world today, Baruch Spinoza. While it is impossible to say whether Spinoza would have supported one of the most liberal and free-thinking sects of modern Judaism, this article will argue that Spinoza changed the course of Jewish theology with his preaching and creation of the idea of ​​the necessity of freedom of religious thought with his works the Theological-Political Treatise. To understand the impact of Spinoza's teachings it is important to first understand his place in the history of Judaism as well as the history of philosophy. Baruch Spinoza was born in 1632 in Amsterdam, where he grew up in a Portuguese-Jewish community. He excelled as a student and was being trained to become a rabbi, but was unable to finish his studies because he was required to help run the family business. At the time Spinoza was a student, a well-informed majority controlled the theology of religious Judaism, its rulings were final, and its control was absolute. Those who spoke out openly against these accepted norms and beliefs would receive the harshest punishments in Jewish circles, the act of Cherem or excommunication, and this was exactly what happened to Spinoza in 1656. Despite the “abominable heresies” for which he was excommunicated are unknown, the reasons are probably related to the radical ideas he presents in his philosophy... mid-paper... century and beyond. The Theological-Political Treatise has the task of laying the foundations on which the most liberal sects of Judaism rest, even if Spinoza himself was not a secular Jew. Without Spinoza it is impossible to know whether the Jewish world would ever have freed itself from the shackles of single religious authority. Works Cited Halper, Edward C. “Spinoza on the Political Value of Freedom of Religion.” History of Philosophy Quarterly (2004): 167-182. http://www.jstor.org/stable/27744984 (accessed November 5, 2011).Mason, Richard. “Spinoza on religious choice”. Philosophy (1994): 443-458. http://www.jstor.org/stable/3751365?seq=1 (accessed 5 November 2011). Nadler, Steven, “Baruch Spinoza,” The Stanford Encyclopedia of Philosophy (Spring 2011 edition), http://plato.stanford.edu/archives/spr2011/entries/spinoza/ (accessed November 7, 2011).