Complex sentence: The six martyred ministers or Sayuksin were six ministers of the Joseon Dynasty who were executed by King Sejo in 1456 for plotting to assassinate him and restore the former king Danjong to the throne.
Split into simpler sentences: The six martyred ministers or Sayuksin were six ministers of the Joseon Dynasty who were executed in 1456. They were executed by King Sejo on the charge of plotting to return Danjong to the throne.