The Emperor of the East is a Caroline era stage play, a tragicomedy written by Philip Massinger and first published in 1632.
Mohun was the uncle of Massinger's friend Sir Aston Cockayne, who contributed a commendatory poem to the 1632 edition.
Mohun was also the son-in-law of Lady Katherine Stanhope, to whom Massinger dedicated his play The Duke of Milan in 1623.
Massinger's primary source for the historical background of his plot was Sir Thomas Hawkins's The Holy Court (1626), a translation of Nicholas Caussin's La cour sainte.
Since the play is a tragicomedy and therefore concludes with a happy ending, Masssinger resolves his plot difficulties by having Theodosius masquerade as clergy and hear his wife's confession, which convinces him that she is innocent of infidelity.