Alexios III Angelos, Latinized as Alexius III Angelus, was Byzantine Emperor from March 1195 to 17/18 July 1203. He reigned under the name Alexios Komnenos associating himself with the Komnenos dynasty. A member of the extended imperial family, Alexios came to the throne after deposing, blinding and imprisoning his younger brother Isaac II Angelos. The most significant event of his reign was the attack of the Fourth Crusade on Constantinople in 1203, on behalf of Alexios IV Angelos. Alexios III took over the defence of the city, which he mismanaged, and then fled the city at night with one of his three daughters. From Adrianople, and then Mosynopolis, he attempted unsuccessfully to rally his supporters, only to end up a captive of Marquis Boniface of Montferrat. He was ransomed and sent to Asia Minor where he plotted against his son-in-law Theodore I Laskaris, but was eventually captured and spent his last days confined to the Monastery of Hyakinthos in Nicaea, where he died.
Alexios V Doukas, Latinized as Alexius V Ducas, was Byzantine emperor from February to April 1204, just prior to the sack of Constantinople by the participants of the Fourth Crusade. His family name was Doukas, but he was also known by the nickname Mourtzouphlos or Murtzuphlus (Μούρτζουφλος), referring to either bushy, overhanging eyebrows or a sullen, gloomy character. He achieved power through a palace coup, killing his predecessors in the process. Though he made vigorous attempts to defend Constantinople from the crusader army, his military efforts proved ineffective. His actions won the support of the mass of the populace, but he alienated the elite of the city. Following the fall, sack, and occupation of the city, Alexios V was blinded by his father-in-law, the ex-emperor Alexios III, and later executed by the new Latin regime. He was the last Byzantine emperor to rule in Constantinople until the Byzantine recapture of Constantinople in 1261.
The 1200s began on January 1, 1200, and ended on December 31, 1209.
Year 1203 (MCCIII) was a common year starting on Wednesday of the Julian calendar. It was also the first year to have all digits different from each other since 1098.
Isaac II Angelos or Angelus was Byzantine Emperor from 1185 to 1195, and co-Emperor with his son Alexios IV Angelos from 1203 to 1204. In a 1185 revolt against the Emperor Andronikos Komnenos, Isaac seized power and rose to the Byzantine throne, establishing the Angelos family as the new imperial dynasty.
Theodore I Laskaris or Lascaris was the first emperor of Nicaea—a successor state of the Byzantine Empire—from 1205 to his death. Although he was born to an obscure aristocratic family, his mother was related to the imperial Komnenos clan. He married Anna, a younger daughter of Emperor Alexios III Angelos in 1200. He received the title of despot before 1203, demonstrating his right to succeed his father-in-law on the throne.
The Fourth Crusade (1202–1204) was a Latin Christian armed expedition called by Pope Innocent III. The stated intent of the expedition was to recapture the Muslim-controlled city of Jerusalem, by first defeating the powerful Egyptian Ayyubid Sultanate. However, a sequence of economic and political events culminated in the Crusader army's 1202 siege of Zara and the 1204 sack of Constantinople, rather than the conquest of Egypt as originally planned. This led to the Partitio terrarum imperii Romaniae or the partition of the Byzantine Empire by the Crusaders and their Venetian allies leading to a period known as Frankokratia, or "Rule of the Franks" in Greek.
The Latin Empire, also referred to as the Latin Empire of Constantinople, was a feudal Crusader state founded by the leaders of the Fourth Crusade on lands captured from the Byzantine Empire. The Latin Empire was intended to replace the Byzantine Empire as the Western-recognized Roman Empire in the east, with a Catholic emperor enthroned in place of the Eastern Orthodox Roman emperors. The main objective of the Latin Empire was planned by Venice, which promoted the creation of this state for their self-benefit.
Alexios IV Angelos, Latinized as Alexius IV Angelus, was Byzantine Emperor from August 1203 to January 1204. He was the son of Emperor Isaac II Angelos and his first wife, an unknown Palaiologina, who became a nun with the name Irene. His paternal uncle was his predecessor Emperor Alexios III Angelos. He is widely regarded as one of the worst Byzantine emperors for calling upon the Fourth Crusade to help him gain power, which ultimately led to the sack of Constantinople.
Boniface I, usually known as Boniface of Montferrat, was the ninth Marquis of Montferrat, a leader of the Fourth Crusade (1201–04) and the king of Thessalonica.
Theodore Branas or Vranas, sometimes called Theodore Komnenos Branas, was a general under the Byzantine Empire and afterwards under the Latin Empire of Constantinople. Under the Latin regime he was given the title Caesar and in 1206 he became governor and lord of Adrianople. He is called Livernas by western chroniclers of the Fourth Crusade, including Geoffroi de Villehardouin.
The House of Laskaris or Lascaris was a Byzantine Greek noble family which rose to prominance during the Late Byzantine period. The members of the family formed the ruling dynasty of the Empire of Nicaea, a Byzantine rump state that existed from the 1204 sack of Constantinople by the Fourth Crusade until the restoration of the Empire under the Palaeologan dynasty in 1261.
The House of Angelos, Latinised as Angelus, was a Byzantine Greek noble family that produced several Emperors and other prominent nobles during the middle and late Byzantine Empire. The family rose to prominence through the marriage of its founder, Constantine Angelos, with Theodora Komnene, the youngest daughter of Emperor Alexios I Komnenos. As imperial relatives, the Angeloi held various high titles and military commands under Emperor Manuel I Komnenos. In 1185, following a revolt against Andronikos I Komnenos, Isaac II Angelos rose to the throne establishing the Angeloi as the new imperial family that ruled until 1204. The period was marked by the decline and fragmentation of the Byzantine Empire, culminating in its dissolution by the Fourth Crusade in 1204 under Alexios IV Angelos.
Constantine Laskaris may have been Byzantine Emperor for a few months from 1204 to early 1205. He is sometimes called "Constantine XI", a numeral now usually reserved for Constantine Palaiologos.
The Byzantine Empire was ruled by emperors of the Angelos dynasty between 1185 and 1204 AD. The Angeloi rose to the throne following the deposition of Andronikos I Komnenos, the last male-line Komnenos to rise to the throne. The Angeloi were female-line descendants of the previous dynasty. While in power, the Angeloi were unable to stop the invasions of the Turks by the Sultanate of Rum, the uprising and resurrection of the Bulgarian Empire, and the loss of the Dalmatian coast and much of the Balkan areas won by Manuel I Komnenos to the Kingdom of Hungary.
The sack of Constantinople occurred in April 1204 and marked the culmination of the Fourth Crusade. Crusader armies captured, looted, and destroyed parts of Constantinople, then the capital of the Byzantine Empire. After the capture of the city, the Latin Empire was established and Baldwin of Flanders was crowned Emperor Baldwin I of Constantinople in the Hagia Sophia.
The siege of Constantinople in 1260 was the failed attempt by the Nicene Empire, the major remnant of the fractured Byzantine Empire, to retake Constantinople from the Latin Empire and re-establish the City as the political, cultural and spiritual capital of a revived Byzantine Empire.
Andronikos Angelos Doukas was a Byzantine aristocrat related to the ruling Komnenos dynasty. During the reign of his cousin, Manuel I Komnenos, he served without success as a military commander against the Seljuk Turks, and as envoy to the Kingdom of Jerusalem. Following Manuel's death, in 1182 he was sent to stop the rebellion of Andronikos I Komnenos, but was defeated and eventually defected to him. Shortly after, he led a failed conspiracy of leading aristocrats against Andronikos I. When it was discovered, Andronikos and his sons fled the Empire, ending up in Acre, where he died. He was the father of emperors Isaac II Angelos and Alexios III Angelos.
The Nicaean–Latin wars were a series of wars between the Latin Empire and the Empire of Nicaea, starting with the dissolution of the Byzantine Empire by the Fourth Crusade in 1204. The Latin Empire was aided by other Crusader states established on Byzantine territory after the Fourth Crusade, as well as the Republic of Venice, while the Empire of Nicaea was assisted occasionally by the Second Bulgarian Empire, and sought the aid of Venice's rival, the Republic of Genoa. The conflict also involved the Greek state of Epirus, which also claimed the Byzantine inheritance and opposed Nicaean hegemony. The Nicaean reconquest of Constantinople in 1261 AD and the restoration of the Byzantine Empire under the Palaiologos dynasty did not end the conflict, as the Byzantines launched on and off efforts to reconquer Southern Greece and the Aegean islands until the 15th century, while the Latin powers, led by the Angevin Kingdom of Naples, tried to restore the Latin Empire and launched attacks on the Byzantine Empire.
The timeline of the Latin Empire is a chronological list of events of the history of the Latin Empire—the crusader state that developed on the ruins of the Byzantine Empire after the Fourth Crusade in the 13th century.
Fourth Crusade 
Byzantine Empire 
Enrico Dandolo 