Constantine IX Monomachos, Latinized as Monomachus, reigned as Byzantine emperor from June 1042 to January 1055. He had been chosen by Empress Zoë Porphyrogenita as a husband and co-emperor in 1042, although she had been exiled for conspiring against her previous husband, Emperor Michael IV the Paphlagonian. They ruled together until Zoë died in 1050.
During Constantine's reign, the Byzantine Empire fought wars against groups which included the Kievan Rus' and the Seljuq Turks. In the year before his death, the split between the Eastern Orthodox and Roman Catholic Churches took place.