Seong Sam-mun was a scholar-official of early Joseon who rose to prominence in the court of King Sejong the Great. He was executed after being implicated in a plot to dethrone King Sejo and restore his predecessor King Danjong, and is known as one of the sayuksin with reference to this plot.

Sejo, personal name Yi Yu, sometimes known as Grand Prince Suyang, was the seventh monarch of the Joseon dynasty of Korea. He was the second son of Sejong the Great and the uncle of King Danjong, against whom he led a coup d'état in 1453.