An Empire is the highest level of landed title in 
Crusader Kings II, above kingdom. The title is held by Emperor-ranked characters only. The portrait of emperor (or equivalent) has a golden border adorned by gems. 
To create or usurp an empire, a character needs to:
- Control at least 80% of its de jure territory
- Hold either two kingdom titles, or an empire-rank title
- Pay 600 wealth plus 400 piety (or equivalent) (wealth cost is gradually reduced as the character amasses piety, with 50% discount at 1000 piety)
- Comply with specific religious and/or cultural conditions (since patch 2.0, most conditions only apply to the AI).
- Comply with any other conditions
Empires are very large and difficult to form. However, emperors' ability to employ kings (or equivalent) as vassals makes management of large realms considerably easier, as is their ability to assimilate kingdoms via de jure drift once the kingdom is fully held by the empire. A Catholic emperor can hold the Papacy as a vassal after successfully pressing an antipope's claim. By granting de jure duchies to the various holy orders, a Catholic emperor can easily terrorise heretic and infidel realms. A Zoroastrian emperor in control of the Persian Empire can reinstate the High Priesthood, creating a religious head for the faith. Once in complete control of the Persian Empire, they can declare themselves the Saoshyant, the One Who Brings Benefit, which enhances their (and their descendants') standing with Zoroastrian vassals.
Additionally, independent dukes within the de jure empire or have the same culture as the emperor are more likely to accept diplomatic vassalization if offered.
The Byzantine Empire exists for all start dates; the Holy Roman Empire for all start dates from 1066 onwards.
In the 
Charlemagne start date at 769, the Abbasids have only recently taken power and are on the ascent; the Holy Roman Empire has yet to exist, but may be formed by decision. In the East, the powerful Empire of Tibet looms over its smaller neighbors. In 
The Old Gods start date at 867, the Arabian Empire is under the control of the collapsing Abbasids, while the Holy Roman Empire may also be formed by decision. The Tibetan Empire has collapsed into a patchwork of warring states by this date.
By 1066, the Arabian Empire has collapsed; the Fatimids control Egypt and a sizeable portion of the former empire. In 1186, the Empire of Rajastan in India appears. The Latin Empire exists between the years 1204 and 1261. The Mongol Empire appears on the map when starting after 1206 and may also spawn as a horde from 1210 if playing from earlier start dates. The successor Mongol Empires of the Golden Horde, the Ilkhanate and the Chagatai Empire appear at the end of 1227. The Deccan Empire will appear only in the last possible start date (The Hundred Years War) in 1337.
If the 
Horse Lords Expansion is active, many more empires are available: independent nomadic rulers, or khagans, hold an empire-tier title and will form titular empires when settling (or custom empires named after the capital county if Charlemagne DLC is also active).
Mechanics unlocked at emperor rank
There are two additional mechanics available to emperors, which are unavailable for lower-ranked rulers; they are tied to the Legalism or Majesty technologies:
- Imperial Administration: Grants automatic "Duchy Viceroyalties" law and revocation of duchy viceroyalty, free vassal retraction, revocation of duchy-level titles (without Charlemagne DLC), and a substantial bonus to vassal limit (+25 bonus; combined with -10 from "Duchy Viceroyalties" law, net increase is +15).
- Viceroyalties (requires Charlemagne DLC): They are lifetime-only title grants that revert to the emperor upon the viceroy's death. The emperor may pass Kingdom Viceroyalty (-5 vassal limit), or both Duchy and Kingdom Viceroyalties (-10 vassal limit).
Those laws are visible on the demesne laws tab; if the 
Conclave DLC is active, the player can find both under the realm laws tab.
The Byzantine Empire starts with both "Imperial Adminstration" and "Duchy Viceroyalties" enacted.
Nomenclature
The proper title of emperor-rank character and their respective land titles are generated according to the combination of their religion, government type, and culture, for instance:
- The Byzantine Emperor is called basileus if their culture group is Byzantine
- A German emperor-tier character is known as kaiser, while a Russian liege is tsar
- An Arabic emperor is known as badshah, while a Turkish liege is padishah
- An Iranian emperor is shahanshah and an Indian liege is called samrat
- An Altaic emperor is known as khagan, while a Tibetan liege is called tsenpo
- A merchant republic liege who attains the emperor-tier title is known as grand prince.
Custom empires
If the Charlemagne DLC is active, rulers can create a custom de jure empire.
This decision is available to an independent king with 8,000 prestige as well as either 180 holdings in their realm, or else three kingdom titles. Custom empires are named after, and take the color of, their creator's primary kingdom (although they can be renamed by owning the Customization Pack DLC).
When formed, all kingdoms either held or entirely controlled by their creator ruler become de jure vassals of the custom empire, so long as their original de jure empire does not exist.
List of empires
| DE JURE EMPIRES | |||||||
| CoA | Empire | Capital | De Jure Kingdoms | Special Requirements | AI additional requirements | ID | Alternate names |
|---|---|---|---|---|---|---|---|
|
Abyssinia | Gondar (883) | Abyssinia, Nubia | King of Egypt, Nubia and Abyssinia | East African culture group | e_abyssinia | |
|
Arabian Empire | Damascus (728) | Arabia, Jerusalem, Egypt, Syria, Yemen 769 only: Maghreb, Africa |
Arabic culture group | e_arabia | ||
|
Bengal Empire | Laksmanavati (1151) | Bengal, Bihar, Gondwana, Kamarupa, Orissa | Empire of India does not exist. | e_bengal | ||
|
Britannia | Middlesex (32) | England, Ireland, Scotland, Wales | English, Anglo-Saxon, or Norman culture, or Celtic or North Germanic culture group | e_britannia | Prydain, Alba | |
|
Byzantine Empire | Constantinople (496) | Anatolia, Armenia, Bulgaria, Croatia, Epirus, Georgia, Greece, Serbia, Sicily, Thrace, Trebizond (& Cyprus, Saruhan, Trinacria, Tekke, Ottoman Turks, Rum, Mentese, Karaman, Germiyan, Eretnid, Aydin, Candar) | Roman Empire does not exist. Latin empire does not exist. Must be Orthodox or Hellenic/Hellenic Reformed. | e_byzantium | ||
|
Carpathia | Pest (522) | Hungary, Wallachia | e_carpathia | |||
|
Deccan Empire | Manyakheta (1210) | Andhra, Karnata, Lanka, Maharastra, Tamilakam, Telingana | Empire of India does not exist. | e_deccan | ||
|
Francia | Paris (112) | All starts: Aquitaine, France, Brittany, Burgundy Additionally in 769: Frisia, Lotharingia |
One kingdom title other than Aquitaine, France, Brittany, or Burgundy | French, Norman, or Occitan culture | e_france | Gallia |
|
Germania | Nassau (121) | 769: Bavaria, Carinthia, Germany, Saxony (& The Hansa) All other starts: None |
Saxon culture or Central Germanic culture group | e_germany | ||
|
Hispania | Toledo (197) | All starts: Andalusia, Navarra 769 and 867: Asturias from 769 to 1147: Badajoz from 769 to 1212: Galicia, Valencia from 1066: Aragon, Castille, León from 1109: Portugal |
No de jure kingdom is held by an infidel (with  Holy Fury)
|
e_spain | ||
|
Holy Roman Empire | Jülich (90) | 769: None All other starts: Bavaria, Carinthia, Frisia, Germany, Lotharingia (& The Hansa) Additionally from 15 September 1066 on: Bohemia |
Can only be created by special decisions. 867 on: requires Catholic or Fraticelli religion, German or Dutch culture, neither the HRE nor Francia exists, the ruler be adult, not a prisoner, not Incapable, 1000 Prestige, 180 Realm Size, Kingdom of Germany and one other Kingdom title, and 2 years of wealth 769: requires Catholic or Fraticelli religion, not holding the Byzantine Empire, the ruler be adult, not a prisoner, not Incapable, 1000 Prestige, 220 Realm Size, holding the Kingdom of Italy or Empire of Italia, a Kingdom or Empire title within Francia, Germania, Britannia, or Hispania, no Christian holder of Francia, Germania, Britannia, or Hispania other than the ruler, 100 opinion with your religious head, and 2 years of wealth. |
e_hre | ||
|
Italia | Rome (333) | Italy, Romagna (Papal States in its place in most bookmarks), Sardinia-Corsica, Venice (& Genoa, Pisa, Naples). |
King of Sicily. (This requirement changes based on de jure drift. You must own all of the following kingdoms if not titular and not de jure Italia: Kingdoms of Sicily, Naples, Trinacria, Italy, Sardinia-Corsica, Romagna, Venice.) |
Italian culture | e_italy | |
|
Kanem-Bornu | None | Hausaland, Kanem | e_kanem | |||
|
Maghreb | Marrakech (843) | 769: none (titular) All other starts: Africa, Maghreb |
Berber culture | e_maghreb | ||
|
Mali | Timbuktu (911) | Ghana, Mali, Songhay | West African culture group | e_mali | ||
|
Persian Empire | Esfahan (646) | Al-Jazira, Daylam, Iraq, Kabulistan, Khorasan, Persia, Sistan | Iranian culture group | e_persia | Parthicum | |
|
Pontic Steppe | Saray (619) | Alania, Crimea, Khazaria | Altaic culture group, Alan culture or Hungarian culture | e_pontic_steppe | ||
|
Rajasthan | Kanyakubja (1356) | Delhi, Gujarat, Kosala, Malwa, Punjab, Rajputana, Sindh | Empire of India does not exist. | e_rajastan | ||
|
Russia | Kiev (547) | Chernigov, Galicia-Volhynia, Kievan Rus, Novgorod, Vladimir | East Slavic, North Germanic or Finno-Ugric culture groups | e_russia | Suomi | |
|
Scandinavia | Uppland (290) | Denmark, Estonia, Finland, Lapland, Norway, Sweden | North Germanic culture group or Finnish culture | e_scandinavia | ||
|
Tartaria | Sarkel (594) | Cumania, Mongolia, Sibir | Altaic culture group | e_tartaria | ||
|
Tibet | Lhasa (1498) | Guge, Kashmir, Kham, Nepal, Yarlung, Xia | e_tibet | Bodchenpo, Tufan, Tubo | ||
|
Turan | Khiva (626) | Khotan, Oghuz, Transoxiana, Zhetysu | e_turkestan | Turkestan | ||
|
Wendish Empire | Krakow (527) | All start dates: Lithuania, Poland, Pomerania Additionally at 769 start: Bohemia Additionally at 867 start: Bohemia, Great Moravia |
West Slavic or Baltic culture groups | e_wendish_empire | ||
|
Volga-Ural | Bulgar (610) | Nenetsia, Perm, Volga Bulgaria | e_idel_ural | |||
| TITULAR EMPIRES | |||||||
| CoA | Empire | Capital | De Jure Kingdoms | Requirements | AI additional requirements | ID | |
|
Aztec Empire | None | N/A | Impossible to create. Always exists once activated. If the Sunset Invasion DLC is active, it can show up somewhere on the Atlantic Coast between 1250 and 1350. | Never | e_mexikha | |
|
Chagatai | Samarkand (903) | N/A | Impossible to create. Exists if you start after 1227. | Never | e_chagatai | |
|
Golden Horde | Saray (619) | N/A | Impossible to create. Always exists once activated. Exists if you start after 1227. | Never | e_golden_horde | |
|
Ilkhanate | Esfahan (646) | N/A | Impossible to create. Always exists once activated. Exists if you start after 1227. | Never | e_il-khanate | |
|
|
India | None | N/A (Inherits everything in India region when formed) | Activated and created by the "Become Samrat Chakravartin" decision. Rajastan, Bengal Empire, and Deccan Empire either do not exist or are held by you. Completely control the India region. 500 gold, 1000 prestige. | e_india | ||
|
Latin Empire | Constantinople (496) | N/A | Catholic religion or Catholic heresy. Neither Byzantine Empire nor Roman Empire exists. Control Kaliopolis and Thrake. | e_latin_empire | ||
|
Mongol Empire | Kara-khorum (1457) | N/A | Activated and created by the "Become Genghis Khan" decision. Must be a nomadic Mongol with 1500 prestige and control of 35 counties. Always exists once activated. Exists if you start between year 1206 and 1227. Almost certainly arrives in Mongolia between 1210 and 1218, if it doesn't already exist. | e_mongol_empire | ||
|
Outremer | Jerusalem (774) | N/A (inherits de jure land of ruler's kingdoms in Near East region and de jure kingdom of Egypt if Egypt is fully controlled) | Activated and created by the "Form an Empire of the Outremer" decision. Requirements: 5000 prestige, Catholic or Fraticelli, not Byzantine/Roman/Holy Roman emperor, king or emperor title in Near East region, complete control of Near East region, County of Jerusalem in demesne. |
Never | e_outremer | |
|
Roman Empire | Rome (333) | N/A (inherits de jure land of player's main title when formed) | Activated and created by the "Restore Roman Empire" decision. Requires Legacy of Rome DLC, Christian religion, 3000 Prestige, full control of duchies of Latium, Venice, Ferrara, Sicily, Genoa, Capua, Apulia, Thrace, Antioch, Jerusalem, Alexandria, Athens, Tunisia and Croatia. With Holy Fury DLC there is also an option to revive Hellenism under a Greek, Italian or Roman Christian Emperor. | e_roman_empire | ||
|
Seljuk Empire | Esfahan (646) | N/A | Impossible to create. Seljuk can appear between 965 and 1200, and if he is successful forms this empire. | Never | e_seljuk_turks | |
|
Slavic Union | Kiev (547) | N/A (inherits as de jure kingdoms of Bohemia, Poland, Chernigov, Galicia-Volhynia, Kievan Rus, Novgorod, Vladimir and Pomerania if Pomerania is fully controlled) | Activated and created by the "Form the Slavic Union" decision. Requirements: 5000 prestige, king or emperor title, complete control of Bohemia, Poland, Chernigov, Galicia-Volhynia, Kievan Rus, Novgorod, Vladimir, culture must be one of Russian, Polish, Bohemian, Volhynian, Ilmenian, Severian, Pomeranian. |
Never | e_lechczechrus | |
|
Timurids | Esfahan (646) | N/A | Impossible to create. Timur can appear between 1350 and 1370, and if he is successful forms this empire. | Never | e_timurids | |
|
Western Protectorate | Dunhuang (1448) | N/A | Impossible to create, for it always exists as a Chinese tributary. Its Chinese Bureaucracy government type makes it unplayable. In games without  , it is largely inactive although it still has a court, and only has a physical presence in 769 and from February 1227 onwards.
|
Never | e_china_west_governor | |