King of Jerusalem in the context of "John of Brienne"

Louis I, also known as Louis the Great (Hungarian: Nagy Lajos; Croatian: Ludovik Veliki; Slovak: Ľudovít Veľký) or Louis the Hungarian (Polish: Ludwik Węgierski; 5 March 1326 – 10 September 1382), was King of Hungary and Croatia from 1342 and King of Poland from 1370 until his death in 1382. He was the first child of Charles I of Hungary and his wife, Elizabeth of Poland, to survive infancy. A 1338 treaty between his father and Casimir III of Poland, Louis's maternal uncle, confirmed Louis's right to inherit the Kingdom of Poland if his uncle died without a son. In exchange, Louis was obliged to assist his uncle to reoccupy the lands that Poland had lost in previous decades. He bore the title Duke of Transylvania between 1339 and 1342 but did not administer the province.

Louis was of age when he succeeded his father in 1342, but his deeply religious mother exerted a powerful influence on him. He inherited a centralized kingdom and a rich treasury from his father. During the first years of his reign, Louis launched a crusade against the Lithuanians and restored royal power in Croatia; his troops defeated a Tatar army, expanding his authority towards the Black Sea. When his brother, Andrew, Duke of Calabria, husband of Queen Joanna I of Naples, was assassinated in 1345, Louis accused the queen of his murder and punishing her became the principal goal of his foreign policy. He launched two campaigns to the Kingdom of Naples between 1347 and 1350. His troops occupied large territories on both occasions, and Louis adopted the styles of Neapolitan sovereigns (including the title of King of Sicily and Jerusalem), but the Holy See never recognized his claim. Louis's arbitrary acts and atrocities committed by his mercenaries made his rule unpopular in Southern Italy. He withdrew all his troops from the Kingdom of Naples in 1351.

Frederick II (Italian: Federico, Sicilian: Fidiricu, German: Friedrich, Latin: Fridericus; 26 December 1194 – 13 December 1250) was King of Sicily from 1198, King of Germany from 1212, King of Italy and Holy Roman Emperor from 1220 and King of Jerusalem from 1225. He was the son of Emperor Henry VI of the Hohenstaufen dynasty (the second son of Emperor Frederick Barbarossa) and Queen Constance I of Sicily of the Hauteville dynasty.

Frederick was one of the most brilliant and powerful figures of the Middle Ages and ruled a vast area, beginning with Sicily and stretching through Italy all the way north to Germany. Viewing himself as a direct successor to the Roman emperors of antiquity, he was Emperor of the Romans from his papal coronation in 1220 until his death; he was also a claimant to the title of King of the Romans from 1212 and unopposed holder of that monarchy from 1215. As such, he was King of Germany, of Italy, and of Burgundy. At the age of three, he was crowned King of Sicily as co-ruler with his mother, Constance, Queen of Sicily, the daughter of Roger II of Sicily. His other royal title was King of Jerusalem by virtue of marriage and his connection with the Sixth Crusade. Frequently at war with the papacy, which was hemmed in between Frederick's lands in northern Italy and his Kingdom of Sicily (the Regno) to the south, he was "excommunicated four times between 1227 and his own death in 1250", and was often vilified in pro-papal chronicles of the time and after. Pope Innocent IV went so far as to declare him preambulus Antichristi (forerunner of the Antichrist).

The Fifth Crusade (September 1217 – August 29, 1221) was a campaign in a series of Crusades by Western Europeans to reacquire Jerusalem and the rest of the Holy Land by first conquering Egypt, ruled by the powerful Ayyubid sultanate, led by al-Adil, brother of Saladin.

After the failure of the Fourth Crusade, Innocent III again called for a crusade, and began organizing Crusading armies led by Andrew II of Hungary and Leopold VI of Austria, soon to be joined by John of Brienne, titular King of Jerusalem. An initial campaign in late 1217 in Syria was inconclusive, and Andrew departed. A German army led by cleric Oliver of Paderborn, and a mixed army of Dutch, Flemish and Frisian soldiers led by William I of Holland, then joined the Crusade in Acre, with a goal of first conquering Egypt, viewed as the key to Jerusalem. There, cardinal Pelagius Galvani arrived as papal legate and de facto leader of the Crusade, supported by John of Brienne and the masters of the Templars, Hospitallers and Teutonic Knights. Holy Roman Emperor Frederick II, who had taken the cross in 1215, did not participate as promised.

Charles III of Naples, also called Charles the Small or Charles of Durazzo (1345 – 24 February 1386), was King of Naples and the titular King of Jerusalem from 1382 to 1386 as Charles III, and also King of Hungary from 1385 to 1386 as Charles II. In 1381, Charles created the chivalric Order of the Ship. In 1383, he succeeded to the Principality of Achaea on the death of James of Baux.

Baldwin I (1060s – 2 April 1118) was the first count of Edessa from 1098 to 1100 and king of Jerusalem from 1100 to his death in 1118. He was the youngest son of Eustace II, Count of Boulogne, and Ida of Lorraine and married a Norman noblewoman, Godehilde of Tosny. He received the County of Verdun in 1096, but he soon joined the crusader army of his brother Godfrey of Bouillon and became one of the most successful commanders of the First Crusade.

While the main crusader army was marching across Asia Minor in 1097, Baldwin and the Norman Tancred launched a separate expedition against Cilicia. Tancred tried to capture Tarsus in September, but Baldwin forced him to leave it, which gave rise to an enduring conflict between them. Baldwin seized important fortresses in the lands to the west of the Euphrates with the assistance of local Armenians. Thoros of Edessa invited him to come to Edessa to fight against the Seljuks. Taking advantage of a riot against Thoros, Baldwin seized the town and established the first Crusader state on 10 March 1098. To strengthen his rule, the widowed Baldwin married an Armenian ruler's daughter (who is now known as Arda). He supplied the main crusader army with food during the siege of Antioch. He defended Edessa against Kerbogha, the governor of Mosul, for three weeks, preventing him from reaching Antioch before the crusaders captured it.

Robert of Anjou (Italian: Roberto d'Angiò), known as Robert the Wise (Italian: Roberto il Saggio; 1276 – 20 January 1343), was King of Naples, titular King of Jerusalem and Count of Provence and Forcalquier from 1309 to 1343, the central figure of Italian politics of his time. He was the third son of King Charles II of Naples and Mary of Hungary, and during his father's lifetime he was styled Duke of Calabria (1296–1309).

Robert's early life was marked by his family's participation in the War of the Sicilian Vespers, in which conflict Robert served as a military commander. Upon the death of his father in 1309, Robert ruled as the king of Naples. His reign brought relative stability to Naples compared to the reigns of his father and grandfather, but it was also marked by rivalries against Germanic powers in northern Italy and the House of Barcelona in the western Mediterranean. Robert was pre-deceased by his son and heir Charles of Calabria, and so willed his throne to his granddaughter, Joanna of Naples.