Madagascar Martyrs' Day. Also found in: Dictionary. Madagascar Martyrs' Day (Commemoration Day, Insurrection Day) Madagascar Martyrs' Day, also known as Commemoration Day or Insurrection Day, officially memorializes those who died in the Revolt of 1947 against the French. Madagascar had been a French colony since 1896 and then was named an overseas territory within the French Union in the 1946 constitution.