How did Marshall rule in marybury v Madison?

In Marbury v. Madison (1803), Chief Justice John Marshall ruled that while William Marbury had a right to his commission, the Supreme Court did not have the jurisdiction to issue a writ of mandamus under the Judiciary Act of 1789, as it conflicted with the Constitution. This landmark decision established the principle of judicial review, allowing the Court to declare laws unconstitutional. Thus, Marshall asserted the authority of the judiciary and reinforced the system of checks and balances among the branches of government.