Modern Judaism is divided into several different fractions whose appearances and values ​​are very different. Although this has become the accepted norm in Judaism, it has not always been this way. Freedom of religious thought in Judaism was considered evil, and preaching these ideas could lead to excommunication from the community. Such was the fate of one of the most important philosophers of the 17th century in today's world, Baruch Spinoza. Although it is impossible to say whether Spinoza would have supported one of the most liberal and free sects of modern Judaism, this article will argue that Spinoza changed the course of Jewish theology with his preaching and the creation of the idea of ​​the necessity of freedom of religious thought with his works the Theological and 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 trained to become a rabbi, but he was unable to complete his studies because he was needed to help run the family business. By the time Spinoza was a student, a well-informed majority controlled the theology of religious Judaism, its decisions final and its control absolute. Those who openly denounced these rules and accepted beliefs would receive the harshest punishments in Jewish circles, the Order of Cherem or excommunication, and this is exactly what happened to Spinoza in 1656. Although the "abominable heresies » why he was excommunicated are unknown, the reasons are probably linked to the radical ideas he presented in his philosopher...... middle of paper...... century and beyond. The Theological-Political Treatise is responsible for laying the foundations on which the most liberal sects of Judaism rely, even though 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 chains of a singular 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 November 5, 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).