The Roman Empire, Eastern Roman Empire, and Romania (Empire) all refer to the political entity of the eastern part of the Roman Empire that, in official history, continued until 1453.
The Byzantine Empire: Tends to refer to the highly Hellenized Eastern Roman Empire after the Heraclian period, and is only used as a historical term in this text.
Basileus/Basilissa: The title of the emperor of the Eastern Roman Empire, derived from the ancient greek words for "tyrant" and "king."
The Disaster of 1204: Refers to the Fourth Crusade. The original destination of the Fourth Crusade was Egypt, under the Ayyubid Dynasty, but due to a series of absurd maneuvers by Venice and Alexius the Younger (Alexios IV Angelos), this Crusade actually evolved into a civil war within the Eastern Roman Empire. After Alexios V Doukas usurped the throne, he intended to renege on the previous agreements and payments between the Angelos Dynasty and the Crusaders. Ultimately, Venice led the Crusaders to conquer Constantinople, destroying the Byzantine Empire and establishing a Latin Empire that adhered to Roman Catholic beliefs. It was not until 1261 that Emperor Michael VIII Palaiologos of the Nicaea Empire recaptured Constantinople and re-established the Eastern Roman Empire. However, after 1204, the national power of the Eastern Roman Empire completely declined, and its original governing order largely collapsed.
Theodoro Principality: Also known as the Goth Principality or Gothia Principality, its capital was Mangup City (in official history, modern-day Sevastopol). Its main ethnic groups were the highly Hellenized Crimean Goths and Greeks in the narrow sense. It was founded in the 13th century and broke away from the rule of the Empire of Trebizond after 1364, existing only as its nominal vassal, and was also a tributary state of the Golden Horde. In official history, it fell in 1475 to the combined attacks of the Ottoman Empire and the Crimean Khanate.
Crimean Goths: In the 3rd century AD, there was a large Goth population in Eastern Europe. They were in constant conflict with the Roman Empire and even severely defeated the Eastern Roman Empire at Adrianople (in official history, modern-day Edirne). Later, in the 4th century, influenced by the expansion of the Hunnic Empire, the Goths began to migrate to the Roman Empire. These westward-migrating Goths eventually destroyed the Western Roman Empire and established several barbarian kingdoms on its ruins, led by the Ostrogothic Kingdom and the Visigothic Kingdom. The remaining few Goths who were unwilling to migrate westward stayed in Crimea and its vicinity. Finally, in the 7th century, under the combined pressure of the Eastern Roman Empire and the Khazar Khanate, the last few independent Goth political entities disappeared. The Goths who were willing to submit to the Roman Empire were settled by the Empire in the southern Crimean Peninsula. These Goths completed their high Hellenization at the latest in the early Komnenos Dynasty, forming a unique group of Crimean Goths. Unlike their other cousins who died out early, they had a Roman identity equivalent to that of the Greeks. In addition, they were also one of the main ethnic groups of the Theodoro Principality. In official history, they were finally completely assimilated by the Tatars in the early 18th century.
Empire of Trebizond: Also known as the Kingdom of Trebizond or the Autocratic State of Trebizond, it was a state established after 1204 by the grandson of Andronikos I Comnenus with the support of the Kingdom of Georgia. It claimed to be the "Roman Empire," but after Michael VIII recaptured Constantinople, it was forced to abandon its claim to the "Roman" title. Since its establishment, it had been continuously encroached upon by Crescent Sect states. In official history, it finally fell in 1461 when the last emperor, David Komnenos, surrendered the city under the fierce assault of the Ottoman Empire.
Republic of Venice: A coastal city-state established by Western Roman survivors, it was initially a vassal of the Eastern Roman Empire and gradually grew stronger with the Empire's connivance. During the time of Alexius I Comnenus, in order to alleviate naval pressure, Alexius I granted Venice quite generous commercial privileges to strengthen and utilize its navy, but this later led to a situation where Venice was bleeding the Empire dry. During the time of Manuel I, an attempt to weaken Venice's influence indirectly led to the massacre of the Venetian community in Constantinople. Later, to collect debts (not really), Venice destroyed the Eastern Roman Empire through the Fourth Crusade and occupied many of its island territories. By 1427, Venice was the strongest naval power in the Mediterranean.
Republic of Genoa: A commercial Republic of comparable renown to Venice in the late Middle Ages. The two often clashed over hegemony in the Eastern Mediterranean, but due to its poor geographical location, Genoa was often caught up in disputes between great powers. In 1427, Genoa nominally submitted to the Duchy of Milan of the Visconti family.
Ottoman Sultanate: The Ottoman, not yet an Empire.
Karaman Beylik: A Turkic Beylik in Asia Minor established in the 13th century, one of the fragments of the Sultanate of Rum, and once a powerful force in Asia Minor, ruling Konya, the former capital of the Sultanate of Rum. However, by 1427, it had become a buffer state between several great powers. Its relationship with the Ottoman had always been poor.
Mamluk Sultanate: Currently the strongest Crescent Sect state in terms of paper strength, its dominion includes but is not limited to Egypt and the Levant. Its rulers originated from Mamluk slave soldiers, and Mamluk slave soldiers in this era generally came from Eastern Orthodox people in the Caucasus and Black Sea region, with Circassian slave soldiers being the most popular.
Kandar Beylik: One of the Beyliks of Asia Minor, it was even able to influence the northern coast of the Black Sea at its peak, but it has now fallen to being a very disobedient lackey of the Ottoman and has a military alliance with Trebizond.
Janik Beyliks: Located in the Janik region, a rather chaotic four to five weak Beyliks with ambiguous relations with the Ottoman.
Aq Qoyunlu Dynasty: A tribal dynasty established by the Turkmen, which had a long-standing confrontation with the Black Sheep Dynasty and a stable royal marriage alliance with Trebizond.
Golden Horde: Also known as the Kipchak Khanate or Jochi Ulus, it was originally the fiefdom of Jochi, the eldest son of Genghis Khan. After the division of the Mongol Empire, it evolved into a powerful force in Eastern Europe. However, by 1427, the once-flourishing Khanate was on the verge of collapse.
Grand Duchy of Moscow: The predecessor of the later Russian Empire, it was still a vassal of the Golden Horde in 1427.