(expanded from the wikipedia article)

Alexius V Ducas, named Mourzophlos for his brooding nature and countenance, swept into power in Byzantium in January of AD 1204. Prior to his usurpation of the imperial throne, he had served as a lightning rod for anti-Latin sentiment since the First Battle of Constantinople in 1203. It would appear that this platform was enough to earn the popular acclaim of the people and the confidence of much of the court — the former had long harboured deep resentment for Italian supremacy in Greek markets and the latter, treacherous by nature to begin with, were less than impressed by Angeloi submission to the Fourth Crusade. Curiously, despite his public derision of the foreigners at the capital’s doorstep, Mourzophlos enjoyed the complete trust of of his cousins Isaac II and Alexius IV, right up until he betrayed them.

On January 27th, AD 1204, Mourzophlos threw down the Angeloi in a palace coup that enjoyed wide-spread public support. By February 5th, he had crowned himself Alexius V Ducas. By the 8th, Alexius IV was dead. The propaganda claimed that it was a sudden illness, but rumour was that he was poisoned and, when he survived that, murdered by Mourzophlos himself. And on the 12th, Isaac II joined his son in the afterlife. Again, the convenient story was sudden illness but who really knew the truth? More importantly, few people south of the Golden Horn actually cared, for Alexius V was wildly popular…

The new emperor was a seasoned intriguer in the viper’s nest that is Blachernae Palace. An indirect descendant of the imperial Ducas family, he had long taken pains to emphasise the glorious nature of his ancestry. Obviously, this meant he was also an indirect descendent some 12 generations removed of the Antonian Palace Prefect of the same name. Indeed, Malachite revealed to the Concord that earlier in his career Alexius was in fact a client to the Cainite and also a member of Ducas’ herd, though he found no evidence that the mortal was ever a ghoul.

Mourzophlos had been married twice but rumours in the capital held that he had long been the lover of Eudokia Angelina, a daughter of Emperor Alexius III Angelus. In 1196, the patronage of the Cainite Ducas saw Mourzophlos, at the age of just 29, rise to the coveted position of protovestiarios to Alexius III. This may have also had something to do with the favour of Eudokia, whom Malachite believed to be a tool of either Nicepherus or Anna Comnena. Ducas only ceased his support of Mourzophlos when he failed to hide his role in the foiled coup of John Comnenus the Fat in AD 1200.

For his role in helping John, Alexius Ducas was imprisoned indefinitely, a noteworthy achievement since every other conspirator was executed in a creative and gruesome manner. Apparently, Ducas’ abandonment of his descendent had as much to do with not being told about the plot as with the fact that it was a clumsy attempt doomed to failure. Malachite stated that he believed that Nicepherus and Anna Comnena, in a rare show of solidarity, forced Ducas to give up Mourzophlos in payment for some matter of internal Family politics.

As a former dupe of the Antonians, Malachite firmly believed that at some point, Alexius Ducas was likely quite aware of the Families. The Nosferatu could not confirm whether the mortal retained any knowledge of Cainites, but he somehow rebuffed Ducas in January, 1204, when the Palace Prefect made an attempt to “enlist” him in order to stabilise the situation at Blachernae.

In any case, his imprisonment would last until the reinstatement to the throne of Isaac II Angelus in July of 1203. Isaac II, along with his son Alexius, were restored through the intervention of certain influential palace nobles as well as the leaders of the 4th Crusade. Isaac II had been deposed and imprisoned by his brother Alexios III in 1195, who had then ordered his guards to blind him so that he would never again be a threat to the throne. Evidently, the people of Constantinople agreed, for when the nobles of Blachernae Palace put Isaac II forward, the people were in full agreement with the 4th Crusade leadership that his son should join him. From there, it proved a simple matter for Alexius Ducas to engineer their downfall, for the father was a broken asset and his son a useless one…

Alexius showed himself to be quite intelligent, proving himself more than able at holding his own in a court renowned for its treachery, and he also appeared to have a flair for military matters, though his talent was largely untested. He was also wise enough to trust to more experienced subordinates such as the brothers Constantine and Theodore Laskaris, both of whom fought the Fourth Crusade with distinction in 1203. He enjoys the respect of much of the soldiery too, for his willingness to lead assaults, albeit never from the front.

Mourzouphlos was cautious as well, and quite paranoid about security, and rightfully so as he survived two assassination in February and March of 1204. The first, on the 6th, was reportedly an attempt by several nobles allied to David and Alexius Comnenus of Trebizond (grandchildren of the late Andronicus), who still harboured a desire to return to the capital and reclaim their birthright. The second, on the 3rd of March, may have been engineered by the Antonian Ducas himself, in an act of revenge after his mortal descendant rebuffed the offer of “assistance” from the Palace Prefect. In both cases, the watchful eyes and ready sword of the famed duelist Romanos of Helenopolis were instrumental in foiling the attempted murder of the new emperor. Malachite was unable to find any evidence that Romanos was a ghoul, a supernatural of any sort, or even in the service of a Cainite, but he reported to the Concord that the man’s skill with a sword was about as great as any mortal man could attain.

Romanos of Helenopolis

The fact that this extraordinary swordsman served his emperor for little more than his friendship and the honour of doing so was a testament to Alexius’ charisma. Malachite reported that he was a natural leader and a skilled orator, especially when it came to whipping up a crowd of commoners into a frenzy. Even so, he appeared to be a genuine patriot, not just a demagogue, and deeply unhappy with the state of the empire. Indeed, Malachite exhibited a genuine respect for the man’s abilities, conviction, and potential, if not his arrogance or lasciviousness.

After attaining the throne, Mourzouphlos made a point of speaking out against the Fourth Crusade at every turn, but he also attempted to negotiate a peaceful outcome if possible. At one point, he even entered into negotiations with Enrico Dandolo personally, but the Doge of Venice attempted to extort unreasonable conditions that he was bound to refuse. Moreover, several Frankish knights also abused the banner of truce and attempted to capture Alexius V for his trouble. It is said that the imprisoned Alexius IV died that very night, which was surely no coincidence, because one of the demands made by the doge was that he be reinstated.

Alexios V negotiating with Doge Enrico Dandalo, by Gustave Doré

Nevertheless, the Concord was aware that the emperor secretly kept the lines of negotiation open throughout all of February and March of 1204. While his soldiers bravely skirmished across the Golden Horn during the day, Alexius V ferried envoys across almost every night, offering the Crusader Barons food and the pledge of future payment of the debt if they quit the city and resumed their journey to the Levant. It is possible that, given their poor funds, shortness of food and low morale, he was merely hoping that stalling an assault would force the pilgrimage into fracturing. He was nearly right. Almost a 1000 men, those with enough money to make it, quit the crusade in March and headed to the Principality of Antioch. Unfortunately, some event in their own ranks appears to have galvanised the resolve of the rest, as the Fourth Crusade began preparing their long-awaited assault as the month of April dawned.

Finally, the Second Battle of Constantinople would begin. Initially, the defenders were successful, managing to hold the walls through an assault on the 9th of April. A second assault on the 12th, however, succeeded in making a breach near the Citadel of Petrion, and suddenly the crusaders were inside the city. The defenders of the city barely had enough numbers to effectively man the walls with veterans, but once the enemy was within, the situation quickly cascaded into disaster. Immediately, the Latins stormed the Blachernae Palace, and more fires were lit to protect their flanks as city guards and Varangians rushed to intercept them.

The emperor himself led a contingent to reclaim the gate of Petrion, but at the site of the bloodthirsty, experienced Franks bearing down upon them most of his own green troops fled, and Alexius V was forced to follow them lest he be captured. Romanos of Helenopolis reportedly fell trying to cover his escape. Within hours, the opportunity to save the city had been lost, and the Great Sack began in earnest. Taking much of what little remained in the treasury, Mourzouphlos fled on a fishing boat to Thrace, and made his way to the city of Mosynopolis in company with Eudokia Angelina, her mother, Euphrosyne Doukaina Kamatera, and their protector, Romanos. There they took shelter with Alexius III, who initially welcomed them.

With the blessing of her father, Alexius Mourzouphlos wed his beloved Eudokia soon after his arrival in Mosynopolis, only to be seized by his father-in-law several months later. Mourzouphlos was then immediately enucleated (blinded) to remove any future threat to Alexius III, and then abandoned when the Angeloi fled the city in November. In this state, he was captured shortly after by Thierry de Loos, the nephew of Geoffrey de Villehardouin, who was leading a Latin Imperial army to conquer Mosynopolis.

Taken back to Constantinople to stand trial for treason against Alexius IV, the blind Mourzouphlos gave a spirited speech in his own defence, claiming that he had merely lawfully slain a traitor himself, as it was young Alexius who had betrayed his country by “leading barbarians and heretics to the very gates of the Queen of Cities.”

Naturally, his insults were received poorly.

Alexius V was executed by the Latins on the 14th of December, 1204.

To make an example of him, they forced the deposed emperor up the internal stairs of the Column of Theodosius before proclaiming his crimes from the top, then hurling him to his death in the forum below. The act was witnessed by a huge crowd of the local Romaioi, presumably gathered under the orders of Emperor Baldwin to impress the authority of the new Latin Imperial regime upon his conquered populace. The pointed lesson was received poorly in turn, for several months later, the Greeks rioted while the emperor’s army marched on Adrianople. The name of Alexius Mourzouphlos was on many of their lips.