How did a case about federalist judges commission lead the supreme court to assert new powers

Marbury Vs. Madison is the case in which the supreme court first asserted the power of Judicial review in finding that the congressional statue expanding the Court's original jurisdiction was unconstitutional. Judicial Review is the power of federal courts to void acts of Congress in conflict with the Constitution. The Supreme Court declared something unconstitutional for the 1st time. The decision is important because it made the Supreme Court a discrete branch of government on par with executive and Congress.