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, the capital of the Greek Christian-controlled Byzantine Empire, rather than 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.
The Empire of Nicaea or the Nicene Empire is the conventional historiographic name for the largest of the three Byzantine Greek rump states founded by the aristocracy of the Byzantine/Roman Empire that fled when Constantinople was occupied by Western European and Venetian armed forces during the Fourth Crusade, a military event known as the Sack of Constantinople. Like the other Byzantine rump states that formed due to the 1204 fracturing of the empire, such as the Empire of Trebizond and the Despotate of Epirus, it was a continuation of the eastern half of the Roman Empire that survived well into the medieval period. A fourth state, known in historiography as the Latin Empire, was established by an army of Crusaders and the Republic of Venice after the capture of Constantinople and the surrounding environs.
The Principality of Achaea or Principality of Morea was one of the vassal states of the Latin Empire, which replaced the Byzantine Empire after the capture of Constantinople during the Fourth Crusade. It became a vassal of the Kingdom of Thessalonica, along with the Duchy of Athens, until Thessalonica was captured by Theodore, the despot of Epirus, in 1224. After this, Achaea became for a while the dominant power in Greece.
The Battle of Pelagonia or Battle of Kastoria took place in early summer or autumn 1259, between the Empire of Nicaea and an anti-Nicaean alliance comprising Despotate of Epirus, Kingdom of Sicily and the Principality of Achaea. It was a decisive event in the history of the Eastern Mediterranean, ensuring the eventual reconquest of Constantinople and the end of the Latin Empire in 1261.
William of Villehardouin was the fourth prince of Achaea in Frankish Greece, from 1246 to 1278. The younger son of Prince Geoffrey I, he held the Barony of Kalamata in fief during the reign of his elder brother Geoffrey II. William ruled Achaea as regent for his brother during Geoffrey's military campaigns against the Greeks of Nicaea, who were the principal enemies of his overlord, the Latin Emperor of Constantinople Baldwin II. William succeeded his childless brother in the summer of 1246. Conflicts between Nicaea and Epirus enabled him to complete the conquest of the Morea in about three years. He captured Monemvasia and built three new fortresses, forcing two previously autonomous tribes, the Tzakones and Melingoi, into submission. He participated in the unsuccessful Egyptian crusade of Louis IX of France, who rewarded him with the right to issue currency in the style of French royal coins.
The Prince of Achaea was the ruler of the Principality of Achaea, one of the crusader states founded in Greece in the aftermath of the Fourth Crusade (1202–1204). Though more or less autonomous, the principality was never a fully independent state, initially being a vassal state subservient of the Latin Empire of Constantinople, which had supplanted the Byzantine Empire, and later of the Angevin Kingdom of Naples. During the Angevin period, the princes were often absent, being represented in the Principality by their baillis, who governed in their name.
The despot of Epirus was the ruler of the Despotate of Epirus, one of the successor states of the Byzantine Empire in the aftermath of the Fourth Crusade. The name "Despotate of Epirus" and the title "despot of Epirus" are modern historiographical names, and were not in use by the despots themselves. In the Byzantine Empire, the title of despot was a prestigious court title and did not designate rule over some specific territory. Though several of the early Greek rulers of the Epirote realm did use the title of despot, it was never in reference to the lands they governed, but instead in reference to their position in the imperial hierarchy.
Geoffrey II of Villehardouin was the third prince of Achaea. From his accession to the princely throne, he was a powerful and respected person, and even French knights came to the principality to enter his service. Geoffrey II emerged as the most powerful vassal of the Latin Empire of Constantinople, the person around whom the crusaders' states in modern Greece gradually regrouped themselves. He came to the rescue of the imperial capital three times. As a reward of his services to the Latin Empire, he was granted suzerainty over the island of Euboea by his brother-in-law, Emperor Baldwin II of Constantinople (1228–1261). He was also a humane prince, benevolent and just, solicitous for the condition of the common people.
The Treaty of Viterbo was a pair of agreements made by Charles I of Sicily with Baldwin II of Constantinople and William II Villehardouin, Prince of Achaea, on 24 and 27 May 1267, which transferred much of the rights to the defunct Latin Empire from Baldwin to Charles.
The Frankokratia, also known as Latinokratia and, for the Venetian domains, Venetokratia or Enetokratia, was the period in Greek history after the Fourth Crusade (1204), when a number of primarily French and Italian states were established by the Partitio terrarum imperii Romaniae on the territory of the dissolved Byzantine Empire.
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.
The Battle of Makryplagi or Makry Plagi was fought between the forces of the Byzantine Empire, and the Latin Principality of Achaea. The Byzantines had been weakened and demoralized by the defection of their numerous Turkish mercenaries to the Achaeans. At Makryplagi, the Byzantines suffered a heavy defeat, which together with their defeat at the Battle of Prinitza the previous year ended their attempted reconquest of the Morea.
Geoffrey of Briel, in older literature Geoffrey of Bruyères, was a French knight and the third lord of the Barony of Karytaina in the Principality of Achaea, in Frankish Greece. He led a colourful and turbulent life, narrated in detail in the Chronicle of the Morea. Accounted the finest knight in the Principality, he fought in the wars against the Byzantine Greeks, was captured in the Battle of Pelagonia in 1259, and was sent back to Achaea bearing the Byzantine terms in 1261. Geoffrey was twice deprived of his barony, once for rebelling against his uncle, the Prince of Achaea William II of Villehardouin, and then for abandoning the Principality without leave in order to spend time with a mistress, the wife of one of his feudatories, in Italy. He was pardoned both times, but henceforth held his title as a gift of the Prince. He died childless in 1275, and the Barony of Karytaina was split up.
This is a timeline of the presence of Eastern Orthodoxy in Greece from 1204 to 1453. The history of Greece traditionally encompasses the study of the Greek people, the areas they ruled historically, as well as the territory now composing the modern state of Greece.
The Empire of Thessalonica is a historiographic term used by some modern scholars to refer to the short-lived Byzantine Greek state centred on the city of Thessalonica between 1224 and 1246 and ruled by the Komnenodoukas dynasty of Epirus. At the time of its establishment, the Empire of Thessalonica, under the capable Theodore Komnenos Doukas, rivaled the Empire of Nicaea and the Second Bulgarian Empire as the strongest state in the region, and aspired to capturing Constantinople, putting an end to the Latin Empire, and restoring the Byzantine Empire that had been extinguished in 1204.
The First Parliament of Ravennika was convened in May 1209 by Latin Emperor Henry of Flanders in the town of Ravennika in Central Greece in an attempt to resolve the rebellion of the Lombard barons of the Kingdom of Thessalonica.
The Second Parliament of Ravennika was convened in May 1210 by Latin Emperor Henry of Flanders in the town of Ravennika in Central Greece in order to resolve the differences between the princes of Frankish Greece and the Roman Catholic clergy of their domains.
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.
County of Edessa [1] 
Principality of Antioch [2] 
Kingdom of Jerusalem [3] 
County of Tripoli [4] 
Kingdom of Cyprus [5] 
Latin Empire [6] 
Kingdom of Thessalonica [7] 
Principality of Achaea [8] [lower-alpha 1] 
Duchy of the Archipelago [9] [lower-alpha 2] 
Terra Mariana [10] 
State of the Teutonic Order [11] 
Hospitaller Rhodes [12] 