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.
When the Roman Empire divided into east and west in 395, the territories of modern Albania became a part of the Byzantine Empire. At the end of the 12th century, the Principality of Arbanon was formed which lasted until mid 13th century, after its dissolution it was followed with the creation of the Albanian Kingdom after an alliance between the Albanian noblemen and Angevin dynasty. After a war against the Byzantine empire led the kingdom occasionally decrease in size until the Angevins eventually lost their rule in Albania and led the territory ruled by several different Albanian chieftains until the mid 14th century which for a short period of time were conquered by the short-lived empire of Serbia. After its fall in 1355 several chieftains regained their rule and significantly expanded until the arrival of the Ottomans after the Battle of Savra.
The Empire of Nicaea or the Nicene Empire was the largest of the three Byzantine Greek rump states founded by the aristocracy of the Byzantine 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 Middle Ages. 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 Epirus in 1224. After this, Achaea became the dominant power in Greece, lasting continuously for 227 years and cumulatively for 229.
Morea was the name of the Peloponnese peninsula in southern Greece during the Middle Ages and the early modern period. The name was used for the Byzantine province known as the Despotate of the Morea, by the Ottoman Empire for the Morea Eyalet, and later by the Republic of Venice for the short-lived Kingdom of the Morea.
Byzantine Greece has a history that mainly coincides with that of the Byzantine Empire itself.
The Despotate of Epirus was one of the Greek successor states of the Byzantine Empire established in the aftermath of the Fourth Crusade in 1204 by a branch of the Angelos dynasty. It claimed to be the legitimate successor of the Byzantine Empire during the subsequent struggle for Constantinople, along with the Empire of Nicaea and the Empire of Trebizond; its rulers briefly proclaiming themselves as Emperors in 1227–1242. The term "Despotate of Epirus" is, like "Byzantine Empire" itself, a modern historiographic convention and not a name in use at the time.
The Empire of Trebizond or the Trapezuntine Empire was one of the three successor rump states of the Byzantine Empire that existed during the 13th through to the 15th century. The empire consisted of the Pontus, or far northeastern corner of Anatolia, and portions of southern Crimea.
Medieval Greece refers to geographic components of the area historically and modernly known as Greece, during the Middle Ages.
The Despotate of the Morea or Despotate of Mystras was a province of the Byzantine Empire which existed between the mid-14th and mid-15th centuries. Its territory varied in size during its existence but eventually grew to include almost all the southern Greek peninsula now known as the Peloponnese, which was known as the Morea during the medieval and early modern periods. The territory was usually ruled by one or more sons of the current Byzantine emperor, who were given the title of despotes. Its capital was the fortified city of Mystras, near ancient Sparta, which became an important centre of the Palaiologan Renaissance.
Thomas Palaiologos was Despot of the Morea from 1428 until the fall of the despotate in 1460, although he continued to claim the title until his death five years later. He was the younger brother of Constantine XI Palaiologos, the final Byzantine emperor. Thomas was appointed as Despot of the Morea by his oldest brother, Emperor John VIII Palaiologos, in 1428, joining his two brothers and other despots Theodore and Constantine, already governing the Morea. Though Theodore proved reluctant to cooperate with his brothers, Thomas and Constantine successfully worked to strengthen the despotate and expand its borders. In 1432, Thomas brought the remaining territories of the Latin Principality of Achaea, established during the Fourth Crusade more than two hundred years earlier, into Byzantine hands by marrying Catherine Zaccaria, heiress to the principality.
The Battle of the Olive Grove of Kountouras took place in the summer of 1205, in Messenia in the Morea peninsula, between the Frankish Crusaders and the local Byzantine Greeks, resulting in a victory of the Franks and the collapse of the local resistance.
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 dismantled Byzantine Empire.
The Despotate of Arta was a despotate established by Albanian rulers during the 14th century, after the defeat of the local Despot of Epirus, Nikephoros II Orsini, by Albanian tribesmen in the Battle of Achelous in 1359. The Despotate ceased to exist in 1416, when it passed to Carlo I Tocco.
The First Ottoman–Venetian War was fought between the Republic of Venice with its allies and the Ottoman Empire from 1463 to 1479. Fought shortly after the capture of Constantinople and the remnants of the Byzantine Empire by the Ottomans, it resulted in the loss of several Venetian holdings in Albania and Greece, most importantly the island of Negroponte (Euboea), which had been a Venetian protectorate for centuries. The war also saw the rapid expansion of the Ottoman navy, which became able to challenge the Venetians and the Knights Hospitaller for supremacy in the Aegean Sea. In the closing years of the war, however, the Republic managed to recoup its losses by the de facto acquisition of the Crusader Kingdom of Cyprus.
The Battle of the Echinades was fought in 1427 among the Echinades islands off western Greece between the fleets of Carlo I Tocco and the Byzantine Empire. The battle was a decisive Byzantine victory, the last in the Empire's naval history, and led to the consolidation of the Peloponnese under the Byzantine Despotate of the Morea.
Since its fall, the issue of succession to the Byzantine Empire has been a major point of contention both geopolitically, with different states laying claim to its legacy and inheritance, and among the surviving members of the Byzantine nobility and their descendants. Historically, the most prominent claims have been those of the Ottoman Empire, which conquered Byzantium in 1453 and ruled from its former capital, Constantinople; the Russian Empire, as the most powerful state practising Eastern Orthodox Christianity; and various nobles and figures in Western Europe of increasingly spurious and questionable imperial descent.
