	Constantine was also a cousin of Eudokia Makrembolitissa, who married Isaac's lieutenant and successor as emperor, Constantine X Doukas, as she too is referred to as a niece of the patriarch. In 1067, Constantine X was dying. Eudokia, as empress-dowager and mother of Constantine's under-age sons, would lead the regency, but Constantine X feared that she might well include her relatives, who already held high posts in court, in the regency, thus posing a potential threat to the succession of Constantine X's own children. He therefore had Eudokia swear publicly that she would not remarry nor appoint any co-regents over her under-age sons with Constantine other than the latter's brother John Doukas, an oath that she would soon break, however, with her marriage to Romanos IV Diogenes.