Emperor Isaac II Angelos ruled the Byzantine Empire from 1187 until 1195, and again more briefly from 1203–04. Born around 1156, he is described as having had a ‘bookish’ education and even his ascent to the throne was something of a paradox. Having resisted the arrest ordered by Emperor Andronikos I, Isaac Angelos found himself acclaimed as Basileos (ruler of the Byzantine Empire) by the people of Constantinople on 12 September 1185. Perhaps because of his own experience of the nobility amongst whom he grew up, Emperor Isaac tended to rely on relatively low-born bureaucrats and foreign soldiers, successfully employing them against aristocratic rebels. While he undoubtedly sold high-ranking positions for money, Isaac also promoted people on merit.
Marriage alliances between Byzantine and other European ruling families had long been common, and Isaac Angelos did the same, taking a daughter of King Béla III of Hungary as his second wife. In his personal life Isaac is said to have preferred an easy life at court but also to be an energetic military campaigner when necessary. He was also accused by the chronicler Nicetas of having a ‘mad passion’ for building, while similarly being responsible for the demolition of several famous churches and monasteries. Unfortunately, Isaac’s policies and the huge problems that the Byzantine Empire faced resulted in very high taxation. This in turn led to resentment, particularly amongst the Vlachs and Bulgarians, who rose in revolt against Byzantine authority. Various other setbacks added to growing discontent, and early in April 1195 Isaac was overthrown and blinded by an aristocratic conspiracy led by his brother, who succeeded him as Emperor Alexios III.
The three other Byzantine rulers at the time of the Fourth Crusade were all named Alexios. The first was Alexios Angelos, who ruled as Emperor Alexios III from 1195 to 1203. Born around 1153, he was the elder brother of Emperor Isaac II and spent several years as a prisoner in the County of Tripoli. This was during the reign of the Byzantine Emperor Andronikos I, who was then succeeded by Isaac. Treated well by Emperor Isaac II, Alexios nevertheless conspired against and eventually overthrew his brother. As a ruler, he appears to have been weak-willed, extravagant and lazy, selecting many senior officials on the basis of who could pay most for the position. On the other hand Alexios III had a strong and effective supporter in his wife Euphrosyne and also enjoyed some military success against Balkan rebels, though the credit for this should go to his generals. He also favoured the merchant republics of Pisa and Genoa over their great rival Venice.
After a brief resistance to the Fourth Crusade, Emperor Alexios III fled, after which he wandered around until captured almost by chance by Boniface of Montferrat late in 1204. The ex-emperor was then sent to northern Italy, where he remained until ransomed – or perhaps more accurately purchased – by Michael I Doukas, the ruler of the Byzantine ‘successor state’ of Epiros. The unfortunate Alexios III was next sent to Ghiyath al-Din Kaykhusraw I, the Saljuq Sultan of Rum in Anatolia, but when Ghiyath al-Din was defeated by Theodore I Laskaris of Nicaea in 1211 the ex-emperor was again captured. This time he was sent to a monastery, where he died within a year.
The young Alexios Angelos IV played a major, if not entirely glorious, role in the Fourth Crusade. Born in 1182 or 1183, the son of Emperor Isaac II Angelos and his first wife, Prince Alexios was apparently left free after the deposition and blinding of his father. Some time during summer or early autumn in 1201 he escaped from Constantinople and made his way to Italy. Failing to gain support there, Alexios Angelos went to Germany, where he was welcomed by his sister Irene, the wife of Philip of Swabia and widow of King Roger III of Sicily. The Byzantine prince was of course at the centre of negotiations about how he might be placed on the imperial throne of Byzantium. During the winter of 1202–03 his envoys and those of Philip of Swabia offered very generous terms to the leaders of the Fourth Crusade, currently camped outside Zadar, if they would support him. Once this had been agreed, Alexios Angelos joined the Crusader army at Corfu in May 1203.
After Alexios III fled and Prince Alexios’ blinded and increasingly incapacitated father Isaac II was restored to the Byzantine throne, the Crusaders demanded that Alexios IV become co-emperor. As his father’s senility worsened, Alexios IV became the dominant ruler, but it also became clear that he could not repay the Crusaders the amount that had been agreed. The young co-emperor now came under the influence of Byzantine leaders who were deeply hostile to the Crusaders. They included Alexios Doukas, and, as Alexios IV became ever more isolated, it was Alexios Doukas who persuaded him to flee. When the Emperor failed to leave Constantinople, Alexios Doukas first imprisoned him and then had him strangled on or around 8 February 1204.
Alexios V Doukas is often portrayed as a ruthless and bloodthirsty opportunist. In reality he attempted to save the Byzantine Empire, but, because he failed, Alexios Doukas became a villain in the eyes of many. Nicknamed ‘Mourtzouphlos’, meaning ‘bushy or overhanging eyebrows’ (this could also be translated as ‘melancholy’, ‘sullen’ or ‘frowning’), he was a member of the aristocratic Doukas family, though his precise lineage is unknown. Some allege that he had been behind an attempted usurpation by John Comnenos, a member of another prominent aristocratic family, back in 1200. Perhaps that was why Alexios Doukas was in prison when the Fourth Crusade appeared off Constantinople. He was apparently still there when Alexios IV became co-emperor, but was released and made protovestiarios, a title that originally indicated the senior official in charge of the imperial wardrobe. Alexios Doukas commanded most of the fighting against the Crusaders outside Constantinople, making him popular in important quarters and facilitating his overthrow of Alexios IV and his coronation as Emperor Alexios V. In particular he won the support of the elite, and by now largely Anglo-Saxon English, Varangian Guard.
During his brief reign Alexios V strengthened the fortifications of the Byzantine capital. Nevertheless, Constantinople eventually fell to Crusader assault and on 12 April 1204 Emperor Alexios V fled to Thrace. There he was captured by the Crusaders, who tried him for treason against Alexios IV and executed him by throwing him from the Column of Theodosios.