Andronikos I Komnenos in the context of "John II Komnenos"

Isaac II Angelos or Angelus (Greek: Ἰσαάκιος Κομνηνός Ἄγγελος, romanized: Isaákios Komnēnós Ángelos; September 1156 – 28 January 1204) was Byzantine Emperor from 1185 to 1195, and co-Emperor with his son Alexios IV Angelos from 1203 to 1204. In an 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.

His father Andronikos Doukas Angelos was a military leader in Asia Minor (c. 1122 – aft. 1185) who married Euphrosyne Kastamonitissa (c. 1125 – aft. 1195). Andronikos Doukas Angelos was the son of Constantine Angelos and Theodora Komnene (b. 15 January 1096/1097), the youngest daughter of Emperor Alexios I Komnenos and Irene Doukaina. Thus Isaac was a member of the extended imperial clan of the Komnenoi.

The Palaiologan army refers to the military forces of the Byzantine Empire under the rule of the Palaiologos dynasty, from the late 13th century to its final collapse in the mid-15th century. The army was a direct continuation of the forces of the Empire of Nicaea, which itself was a fractured component of the formidable Komnenian army of the 12th century. Under the first Palaiologan emperor, Michael VIII, the army's role took an increasingly offensive role whilst the naval forces of the empire, weakened since the days of Andronikos I Komnenos, were boosted to include thousands of skilled sailors and some 80 ships. Due to the lack of land to support the army, the empire required the use of large numbers of mercenaries.

After Andronikos II took to the throne in 1282, the army fell apart and the Byzantines suffered regular defeats at the hands of their eastern opponents, although they would continue to enjoy success against the Latin territories in Greece. By c. 1350 the Empire's inefficient fiscal organization and incompetent central government made raising troops and the supplies to maintain them a near-impossible task, and the Empire came to rely upon troops provided by Serbs, Bulgarians, Venetians, Latins, Genoese and Turks to fight the civil wars that lasted for the greater part of the 14th century, with the latter foe being the most successful in establishing a foothold in Thrace. By the time the civil war had ended, the Turks had cut off Constantinople, the capital of the Byzantine Empire, from the surrounding land and in 1453 the last decisive battle was fought by the Palaiologan army when the capital was stormed and sacked, falling on 29 May.

The Byzantine Empire was ruled by emperors of the Komnenos dynasty for a period of 104 years, from 1081 to about 1185. The Komnenian (also spelled Comnenian) period comprises the reigns of five emperors, Alexios I, John II, Manuel I, Alexios II and Andronikos I. It was a period of sustained, though ultimately incomplete, restoration of the military, territorial, economic and political position of the Byzantine Empire.

Byzantium under the Komnenoi played a key role in the history of the Crusades in the Holy Land, while also exerting enormous cultural and political influence in Europe, the Near East, and the lands around the Mediterranean Sea. The Komnenian emperors, particularly John and Manuel, exerted great influence over the Crusader states of Outremer, whilst Alexios I played a key role in the course of the First Crusade, which he helped bring about.

Alexios I Megas Komnenos (Greek: Αλέξιος Κομνηνός; Georgian: ალექსი კომნენოსი; c. 1182 – 1 February 1222) or Alexius I Megas Comnenus with his brother David, the founder of the Empire of Trebizond and its ruler from 1204 until his death in 1222. The two brothers were the only male descendants of the Byzantine Emperor Andronikos I, who had been dethroned and killed in 1185, and thus claimed to represent the legitimate government of the Empire following the conquest of Constantinople by the Fourth Crusade in 1204. Although his rivals governing the Nicaean Empire succeeded in becoming the de facto successors, and rendered his dynastic claims to the imperial throne moot, Alexios' descendants continued to emphasize both their heritage and connection to the Komnenian dynasty by later referring to themselves as Megas Komnenos ("grand Komnenos").

While his brother David conquered a number of Byzantine provinces in northwestern Anatolia, Alexios defended his capital Trebizond from an unsuccessful siege by the Seljuk Turks around the year 1205. Further details of his reign are sparse. Muslim chroniclers record how, in 1214, Alexios was captured by the Turks in the field while defending Sinope; despite sending an envoy to seek their surrender the city refused to capitulate to Sultan Kaykaus I, and Alexios was tortured in sight of the Sinopians. The city submitted to Kaykaus and Alexios was freed after becoming Kaykaus' vassal. Alexios died at the age of forty.

The Trapezuntine emperors were the rulers of the Empire of Trebizond, one of the successor states of the Byzantine Empire founded after the Fourth Crusade in 1204, until its fall to the Ottoman Empire in 1461. All but two of the Trapezuntine rulers belonged to the Komnenos dynasty, which had previously ruled the Byzantine Empire from 1081 to 1185. They initially claimed to represent the legitimate line of Roman emperors, in opposition to the Latin Empire in Constantinople, the Laskaris dynasty of the Nicene Empire, and the Komnenos Doukas family of Epirus and Thessalonica. To emphasize their dynastic claim, Trapezuntine emperors from the late 13th century onwards styled themselves as Megas Komnenos (Μέγας Κομνηνός, lit. 'Grand Komnenos').

Out of the Byzantine claimants that emerged in 1204 and thereafter, the Trapezuntine emperors, despite their illustrious descent, had perhaps the worst position. Not only were they far away from Constantinople in a peripheral province of the empire, but the reputation of the Komnenoi had been severely damaged by the detested last emperor of the dynasty, Andronikos I Komnenos (r. 1183–1185), grandfather of the first Trapezuntine emperor Alexios I (r. 1204–1222). Though they continued to claim to be the legitimate rulers of the entire former Byzantine Empire for decades thereafter, conflict with the Nicene Empire and the Sultanate of Rum in the early 13th century reduced the power of the Trapezuntine emperors. After the fall of Sinope to Sultan Kaykaus I in 1214, the Empire of Trebizond ceased to be a major contender for restoring the Byzantine Empire and became reduced to a small and local power.

The House of Komnenos (pl. Komnenoi; Greek: Κομνηνός, pl. Κομνηνοί, pronounced [komniˈni]), Latinized as Comnenus (pl. Comneni), was a Byzantine Greek noble family who ruled the Byzantine Empire in the 11th and 12th centuries. The first reigning member, Isaac I Komnenos, ruled from 1057 to 1059. The family returned to power under Alexios I Komnenos in 1081 who established their rule for the following 104 years until it ended with Andronikos I Komnenos in 1185. In the 13th century, they founded the Empire of Trebizond, a Byzantine rump state which they ruled from 1204 to 1461. At that time, they were commonly referred to as Grand Komnenoi (Μεγαλοκομνηνοί, Megalokomnenoi), a style that was officially adopted and used by George Komnenos and his successors. Through intermarriages with other noble families, notably the Doukas, Angelos, and Palaiologos, the Komnenos name appears among most of the major noble houses of the late Byzantine world.

The House of Angelos (/ˈændʒəloʊs, ˈæŋɡəloʊs/; pl. Angeloi; Greek: Ἄγγελος, pl. Ἄγγελοι) 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.

After the Fourth Crusade, another branch of the family managed to establish an independent state in Epirus, which quickly expanded to rule Thessaly and Macedonia. The members of this branch largely eschewed the use of the 'Angelos' surname in favour of the more prestigious 'Doukas' and 'Komnenos', and are collectively known as the Komnenodoukas (Κομνηνοδούκας) dynasty. In c. 1224, Theodore Komnenos Doukas conquered Thessalonica, and founded the Empire of Thessalonica, claiming the Byzantine imperial title in rivalry to the Empire of Nicaea. His empire quickly collapsed after the Battle of Klokotnitsa in 1230. Thessalonica was lost to Nicaea in 1246, and the prospects of recovering Constantinople were dashed at the Battle of Pelagonia in 1259, followed by the re-establishment of the Byzantine Empire under the Palaiologos dynasty in 1261. Often in rivalry to the new Byzantine regime, the Komnenodoukai nevertheless secured recognition and titles from Constantinople, and retained their control over Thessaly (ruled by a cadet line) and Epirus until 1318.
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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.

Infighting among the elite saw Byzantium lose substantial financial capability and military power. The previous policies of openness with Western Europe, followed by the sudden massacre of Latins under Andronikos, had preceded the rule of the Angeloi making enemies among Western European states. The weakening of the empire under the Angeloi dynasty resulted in the partitioning of the Byzantine Empire when in 1204, soldiers of the Fourth Crusade overthrew the last Angeloi Emperor, Alexios V Doukas.