Why is the Marshall Court considered so central to the nation's history

Whereas previous Chief Justices of the Supreme Court (John Jay, John Rutledge, and Oliver Ellsworth) left little real mark behind in there tenures, Marshall established several principles essential to the modern Supreme Court.

Most essential, in the Marbury v Madison case, his court established that the Supreme Court had the authority to overrule both laws of Congress, and the states, as well as executive acts if the court rules them to be in direct violation of the Constitution.

Believe it or not, Judicial Review was not originally initially in the constitution as defined above, and Marshall's court established it as a power in the Judical branch.