Second Crusade in the context of "Christian forces of the First Crusade"

The Crusades were a series of military campaigns launched by the papacy between 1095 and 1291 against Muslim rulers for the recovery and defence of the Holy Land (Palestine), encouraged by promises of spiritual reward. The First Crusade was proclaimed by Pope Urban II at the Council of Clermont on 27 November 1095 in response to a Byzantine appeal for aid against the advancing Seljuk Turks. By this time, the papacy's position as head of the Catholic Church had strengthened, and earlier conflicts with secular rulers and wars on Western Christendom's frontiers had prepared it for the direction of armed force in religious causes. The First Crusade led to the creation of four Crusader states in the Middle East, whose defence required further expeditions from Catholic Europe. The organisation of such large-scale campaigns demanded complex religious, social, and economic institutions, including crusade indulgences, military orders, and the taxation of clerical income. Over time, the crusading movement expanded to include campaigns against pagans, Christian dissidents, and other enemies of the papacy, promoted with similar spiritual rewards and continuing into the 18th century.

The Crusade of 1101, the earliest papally sanctioned expedition inspired by the First Crusade, ended in disastrous defeats. For several decades thereafter, only smaller expeditions reached the Holy Land, yet their role in consolidating and expanding the Crusader states was pivotal. The fall of Edessa, the capital of the first Crusader state, prompted the Second Crusade, which failed in 1148. Its failure reduced support for crusading across Latin Christendom, leaving the Crusader states unable to resist Saladin's expansion. Having united Egypt and Muslim Syria under his rule, Saladin destroyed their combined armies at the Battle of Hattin in 1187. The Crusader states survived largely owing to the Third Crusade, a major campaign against Saladin, though Jerusalem remained under Muslim control. Initially directed against Egypt, the Fourth Crusade was diverted to the Byzantine Empire, culminating in the Sack of Constantinople and the establishment of the Latin Empire in 1204. The Fifth Crusade again targeted Egypt but failed to conquer it in 1219–21. By this period, crusade indulgences could also be obtained through other campaigns—such as the Iberian, Albigensian, and Northern Crusades—thereby diminishing enthusiasm for expeditions in the eastern Mediterranean.

The Crusader states, or Outremer, were four Catholic polities established in the Levant region and southeastern Anatolia from 1098 to 1291. Following the principles of feudalism, the foundation for these polities was laid by the First Crusade, which was proclaimed by the Latin Church in 1095 in order to reclaim the Holy Land after it was lost to the 7th-century Muslim conquest. From north to south, they were: the County of Edessa (1098–1150), the Principality of Antioch (1098–1268), the County of Tripoli (1102–1289), and the Kingdom of Jerusalem (1099–1291).

The three northern states covered an area in what is now southeastern Turkey, northwestern Syria, and northern Lebanon; the Kingdom of Jerusalem, the southernmost and most prominent state, covered an area in what is now Israel, Palestine, southern Lebanon, and western Jordan. The description "Crusader states" can be misleading, as from 1130 onwards, very few people among the Franks were Crusaders. Medieval and modern writers use the term "Outremer" as a synonym, derived from the French word for overseas.

Eleanor of Aquitaine (French: Aliénor d'Aquitaine or Éléonore d'Aquitaine; Occitan: Alienòr d'Aquitània [aljeˈnɔɾ dakiˈtanjɔ]; Latin: Helienordis, Alienorde or Alianor; c. 1124 – 1 April 1204) was duchess of Aquitaine from 1137 to 1204, queen of France from 1137 to 1152 as the wife of King Louis VII, and queen of England from 1154 to 1189 as the wife of King Henry II. As the reigning duchess of Aquitaine, she ruled jointly with her husbands and two of her sons, Kings Richard I and John of England. As the heiress of the House of Poitiers, which controlled much of southwestern France, she was one of the wealthiest and most powerful people in Western Europe during the High Middle Ages.

The eldest child of Duke William X of Aquitaine and Aénor de Châtellerault, Eleanor became duchess upon her father's death in 1137. Later that year, she married Louis, son of King Louis VI of France. Shortly afterwards, Eleanor's father-in-law died and her husband became king, making her queen consort. Louis VII and Eleanor had two daughters, Marie and Alix. During the Second Crusade, Eleanor accompanied Louis to the Holy Land. Pope Eugene III rejected an initial request in 1149 for an annulment of the marriage on grounds of consanguinity. In 1152, after fifteen years of marriage, Eleanor had not borne a male heir, and the annulment was granted. Their daughters were declared legitimate, custody was awarded to Louis, and Eleanor's lands were restored to her.

The second Battle of Dorylaeum took place near Dorylaeum in October 1147, during the Second Crusade. It was not a single clash but consisted of a series of encounters over a number of days. The German crusader forces of Conrad III were defeated by the Seljuk Turks led by Sultan Mesud I.

The siege of Edessa took place from 28 November to 24 December 1144, resulting in the fall of the capital of the County of Edessa to Zengi, the atabeg of Mosul and Aleppo. This event was the catalyst for the Second Crusade.

Géza II (Hungarian: II. Géza; Croatian: Gejza II.; Slovak: Gejza II.; 1130 – 31 May 1162) was King of Hungary and Croatia from 1141 to 1162. He was the oldest son of Béla the Blind and his wife, Helena of Serbia. When his father died, Géza was still a child and he started ruling under the guardianship of his mother and her brother, Beloš. A pretender to the throne, Boris Kalamanos, who had already claimed Hungary during Béla the Blind's reign, temporarily captured Pressburg (now Bratislava in Slovakia) with the assistance of German mercenaries in early 1146. In retaliation, Géza who came of age in the same year, invaded Austria and routed Henry Jasomirgott, Margrave of Austria, in the Battle of the Fischa.

Although the German–Hungarian relations remained tense, no major confrontations occurred when the German crusaders marched through Hungary in June 1147. Two months later, Louis VII of France and his crusaders arrived, along with Boris Kalamanos who attempted to take advantage of the crusade to return to Hungary. Louis VII refused to extradite Boris to Géza, but prevented the pretender from contacting his supporters in Hungary and managed to shepherd him to Constantinople with the rest of the crusaders. Géza joined the coalition that Louis VII and Roger II of Sicily formed against Conrad III of Germany and Byzantine emperor Manuel I Komnenos.

Manuel I Komnenos (Greek: Μανουήλ Κομνηνός, romanized: Manouḗl Komnēnós; 28 November 1118 – 24 September 1180), Latinized as Comnenus, also called Porphyrogenitus (Greek: Πορφυρογέννητος, romanized: Porphyrogénnētos; "born in the purple"), was a Byzantine emperor of the 12th century who reigned over a crucial turning point in the history of Byzantium and the Mediterranean. His reign saw the last flowering of the Komnenian restoration, during which the Byzantine Empire experienced a resurgence of military and economic power and enjoyed a cultural revival.

Eager to restore his empire to its past glories as the great power of the Mediterranean world, Manuel pursued an energetic and ambitious foreign policy. In the process he made alliances with Pope Adrian IV and the resurgent West. He invaded the Norman Kingdom of Sicily, although unsuccessfully, being the last Eastern Roman emperor to attempt reconquests in the western Mediterranean. The passage of the potentially dangerous Second Crusade through his empire was adroitly managed. Manuel established a Byzantine protectorate over the Crusader states of Outremer. Facing Muslim advances in the Holy Land, he made common cause with the Kingdom of Jerusalem and participated in a combined invasion of Fatimid Egypt. Manuel reshaped the political maps of the Balkans and the eastern Mediterranean, placing the kingdoms of Hungary and Outremer under Byzantine hegemony and campaigning aggressively against his neighbours both in the west and in the east.