Byzantine Chronicle

Zeno(474-475 & 476-491)

According to a popular legend recorded by two ancient historians, emperor Zeno died when he was buried alive after loosing his senses, either because of epilepsy or as a result of heavy drinking.
He called for help when awoke but he was already in the sarcophagus and empress Ariadne did not allow to open it.
Zeno, officially, died of dysentery.

Basiliscus(475-476)

Basiliscus was an usurper who exploited the unpopularity of Zeno to become emperor. Zeno managed to gather an army against him and eventually Basiliscus was forced to abdicate and surrender.
He was killed together with his family. Zeno had promised not to shed their blood, so he gave orders to leave them to die -without food and water- in a dry cistern.

Maurice(582-602)

Maurice lost his throne after a mutiny of the troops in Thrace who rebelled when they received orders to stay during the winter in enemy territory, north of Danube. One of the leaders of the rebellion, Phocas, became emperor.
It was the first coup d’ etat after the foundation of Constantinople. Maurice was tortured to death after he was forced to watch the execution of his six sons.

Phocas(602-610)

Maurice was the first emperor killed by his successor, Phocas. The second was Phocas. After the successful rebellion of Heraclios, Phocas was captured and brought before Heraclios, who asked, "Is this how you have ruled, wretch?"
Phocas replied, "And will you rule better?"
Enraged, Heraclios killed and beheaded Phocas on the spot. Phocas' body was mutilated, paraded through the capital, and burned.

Leo IV the Khazar(775-780)

Leo IV officially died of fever. The rumour was that he had died of an illness contracted after taking and wearing on his head the jewelled crown from the Church of St Sophia, which had been dedicated there by Maurice or Heraclios. His head developed carbuncles and was seized by a violent fever.

It is, however, very possible that his wife, the notorious Irene, deliberately had this strange story circulated, in an attempt to smear her husband's memory .

Nikephoros I Logothetes(802-811)

Nikephoros I was killed fighting against the Bulgars, in the disastrous battle of Pliska, where a Byzantine army of 80,000 was destroyed. The victorious King Krum had the dead Roman Emperor's skull made into a silver-lined goblet from which visiting Byzantine ambassadors were thereafter forced to drink a toast.

Leo V  the Armenian(813-820)

Leo V was murdered inside the Palace chapel on Christmas day by the supporters of Michael II, who were disguised as monks. Michael II was in jail at the time of the murder and was crowned hastily, while still in prison chains (they could not found the key)

Basil I  the Macedonian(867-886)

Basil I, while hunting in Thrace, was thrown from his horse and impaled on the horns of a stag, which carried him for sixteen miles before it was hunted down. One of the attendants finally caught them and drew his hunting-knife, and, cutting the girdle, saved the emperor's life; but the suspicious despot, fearing an attempt at assassination, ordered his faithful servant to be immediately decapitated.
The shock he received from the stag brought on a fever, which terminated his eventful life.

Alexander(912-913)

Alexander died of exhaustion -probably a heart attack- after a game of tzykanion which was a popular, upper-class game with horses, very similar to the modern polo. Leo the Wise had prophesied that his brother, Alexander, would reign for 13 months only (as it happened).

Nikephoros II Phocas(963-969)

Nikephoros II Phocas was murdered by a gang of conspirators who were led by John Tzimiskes. They had entered the palace dressed as women, with the help of the empress Theophano. Tzimiskes and the others sneaked into his bed chamber, alarmed at first to find the bed empty because Nikephoros frequently slept on the floor, but finally they found and killed the emperor.
His head was cut off and paraded on a spike, while his body was thrown out the window. His death shook Christians and caused joy in the Muslim world. An inscription carved on the side of his tomb read: "You conquered all but a woman".

John II Komnenos(1118-1143)

John Komnenos died in a hunting accident in the mountains of Cilicia, when he grazed himself with a poisoned arrow which was put out from a wounded boar. There had been the usual speculations that it was not really an accident but there were no motives nor suspects for such an action.

Andronikos I Komnenos(1183-1185)

Andronikos I Komnenos had established a state of terror. When his people tried to arrest a suspect aristocrat, Isaac Angelos, the people revolted and proclaimed Isaac emperor.
Isaac handed him over to the city mob and for three days he was exposed to their fury and resentment, remaining for that period tied to a post and beaten.
His right hand was cut off, his teeth and hair were pulled out, one of his eyes was gouged out, and, among many other sufferings, boiling water was thrown in his face, punishment probably associated with his handsomeness and life of licentiousness. At last, led to the Hippodrome of Constantinople, he was hung up by the feet between two pillars, and two Latin soldiers competed as to whose sword would penetrate his body more deeply, and finally his body, according to the representation of his death, was torn apart.

Alexios V Doukas Murtzuphlos(1204)

Alexios V Doukas was emperor when Constantinople fell to the Crusaders. He fled to Mosynopolis, the base of the ex-emperor Alexios III. At first he was received well and Alexios III married him with his daughter who already was Alexios V's lover. However, later, Alexios V was ambushed in the baths and was blinded on the orders of his father-in -law.
After that, he was released and was wandering helpless the streets. There, he was found by Latin soldiers and was brought back to Constantinople. The new rulers of Byzantium sentenced him to death for treason against their ally, Alexios IV.
He was thrown from the top of the column of Theodosius. An unusual death even for Byzantine standards.
However, the Franks had a reason for this absurdity: One of the prophesies of the emperor Leo VI predicted that the last Roman emperor would die exactly like this, falling from the column of Theodosius. So, apparently, the Franks wanted to prove that the prophesy had been fulfilled and a new era had begun.

John V Palaiologos(1341-1391)

John V Palaiologos had to swallow many humiliations during his long reign: he was jailed for bad debts by the Venetians, he had to become a Catholic, he kissed Pope's feet, he was deposed 3 times, his son was kept hostage by the Turks etc. He could not take the last humiliation:
In 1390 he tried to repair the Golden Gate of the walls using marble from the the decayed churches of the city. Upon termination of works, the Turk sultan Bayazid I, threatening to murder his son Manuel who was kept as a hostage, demanded to raze the newly erected wall enforcement. John V was forced to obey and destroy the construction. This incident was the last drop. He suffered a severe breakdown.
He never recovered and died a couple of months later.