Why was marbury v Madison considered a landmark Supreme Court case

At the time, the government was considered to be democratic, the only federalist officers were the judges. In marbury v Madison the judge, was a federalist (Judge Marshall). What happened was Jefferson order the Secretary of state to not deliver commissions to federalist judges. Marybury sued for commissions, which created the case. What was significant was Marshall used the judiciary act to rule Marbury had commission, but it gave the court grater power than the constitution make the act unconstitutional. Marbury lost the case but the federalist judges won in the end. This case created Judicial review which let the supreme court exercise the power to decide weather an act of congress was allowed by the constitution. This gave the judges more power