The research addresses Baruch de Spinoza s philosophy on freedom of philosophizing and expression and, consequently, religious freedom, considering the philosophies of toleration of the 17th century and the trial of Izaque de Castro Tartas before the Lisbon Inquisition. Given that Spinoza does not use the term tolerance in his writings, the research analyzes how Spinoza s philosophy goes beyond the philosophies of toleration, in the words of Filippo Mignini. The resonance of crypto-Jewish thought in Spinoza s philosophy is essential to understand the formulation of his radical conception of freedom, placing him in direct conflict with the theological-political powers of the monarchies and Iberian Inquisitions of the 17th century. The Lisbon Inquisition trial of Izaque de Castro Tartas, who lived with Spinoza in the Jewish community of Amsterdam in the 1640s, highlights an essential convergence with Spinoza under influence of Uriel da Costa and Juan de Prado: the adoption of natural law in defense of religious freedom and expression. In his case, Izaque defended the relationship between natural law and jus gentium to ensure the protection of religious freedom guaranteed in Clause XXV of the Treaty of Truce of 1641, providing a unique perspective for understanding the history of international law. The convergences between Izaque and Spinoza demonstrate a radical defense of freedom of philosophy, religion and expression in the 17th century, which were marked by crypto-Jewish influences and went beyond the discourses of tolerance of the 17th century, in direct resistance to theological-political powers.