Constantine X Doukas (1059–1067) let the Byzantine army decay while the Seljuk Turks probed Anatolia — the neglect that Manzikert would price four years after his death.
Constantine X was the civil establishment's emperor: a Doukas aristocrat raised to the purple in 1059 when Isaac I Komnenos, the reforming soldier, abdicated in illness and disillusion. The bureaucracy and the intellectuals — his patron was the philosopher-politician Michael Psellos — got the ruler they wanted.
The army paid. Budgets were slashed, frontier corps disbanded, commands sold; and in his very reign the price appeared — Armenia's capital Ani fell to Alp Arslan in 1064, and Turkish raiders wintered inside Anatolia. He died in 1067 leaving boys, a bound widow, and a broken shield.
Born around 1006 into the Doukai — one of the oldest names of the Anatolian aristocracy, by his generation thoroughly domesticated into the capital's civil elite — Constantine rose through court dignities and a fortunate second marriage to Eudokia Makrembolitissa, niece of the patriarch Michael Keroularios.
He backed Isaac Komnenos's military coup of 1057, and when Isaac's reforming zeal exhausted the establishment and his own health, Psellos engineered the succession: Isaac abdicated into a monastery in November 1059, and Constantine — the safe, senatorial choice — took the throne.
Psellos's Chronographia, our fullest source, praises his friend and creature warmly — gentle, just, pious, a lover of learning and of legal niceties who would rather, he said, be remembered as a man of letters than as emperor — and the praise damns him. Even Psellos concedes the military men despised the regime; the historian Attaleiates, who watched the eastern collapse, is openly contemptuous of an emperor who economised on soldiers while multiplying court stipends.
His obsessive dynasticism completed the damage: crowning his small sons, exacting the famous oath from Eudokia never to remarry, binding the senate to his children — arrangements designed to keep the Doukai in power, which they did, at the cost of paralysing the empire's response in the crisis years that followed.
The reign's ledger is short on events and long on erosion: the Hungarian capture of Belgrade, the Uze crossing of the Danube in 1064 bought off with gold and smallpox, and in the east the methodical Seljuk advance — Ani sacked in 1064, Caesarea plundered by Turkish bands operating hundreds of miles inside the frontier. The tagmatic field armies shrank as pay and rolls were cut; Armenian buffer principalities, annexed by his predecessors, were left ungarrisoned.
When he died on 23 May 1067 the establishment attempted government by regency — Eudokia and the children, Psellos advising — but within months the scale of the Turkish emergency forced the capital to accept what Constantine had tried to forbid: the empress's remarriage to a fighting general, Romanos Diogenes.
Manzikert happened in 1071, but the historians who lived through it — Attaleiates above all — dated the disaster from Constantine's economies: the army Romanos led east was, they insist, a shadow force of unpaid veterans and raw hirelings precisely because of the Doukas decade. Modern Byzantinists broadly concur that the 1060s neglect, more than the battle itself, opened Anatolia.
His dynasty outlived his empire's heartland: the Doukai supplied the next emperor but one, married into the Komnenoi, and their name ran on in the aristocracy for centuries — the family project succeeding exactly as the imperial one failed.