Constantin IX Monomaque (1000 - January 11th 1055) was Byzantine emperor of 1042 with 1055. He married initially a noble Byzantine, Pulchérie Sklérina († 1042), and had as a child Marie Monomaque († 1067), married to Vsevolod Ier, large-duke of Kiev.

It remarie the June 11th 1042 with the empress Zoe (978 † 1050), of which he was the lover and who associates it with the imperial throne. After his marriage, Constantin carried out a quasi marital life with a niece of his first wife, called Sklérène , which died of a lung disease in March 1044.

Its reign is marked by the weakening of the provincial administration, the consolidation of the feudal power and the loss of the sicilian and Italian possessions of Byzance.

Constantin IX, by his imaginations, contributed to the exhaustion of the imperial treasure which its predecessors had accumulated. This treasure will miss cruelly for the fight which will begin later against the Turks.

It had to fight the insurrections of Georges Maniakès in 1043 and of Leon Tornikios in 1047, to fight against the appearance of new enemies, the Turks Seldjoukide S in the East, the Norman ones, the Petchenègues, Oghouz and the Coumans in Occident, and to face the schism of 1054 between Rome and Constantinople.

In spite of the successive disasters which marked its reign, Constantin IX encouraged arts and sciences, being surrounded able men, among whom the historian Michel Psellos, the lawyer Jean Xiphilin, the poet Jean Mauropous and the administrator Constantin Likhoudès: it is with these men that one owes the rebirth, in 1045, of the University of Constantinople.

Remained only emperor with died of Zoe in 1050, Constantin IX died the January 11th 1055 of Pleurésie.