Beginning the siege of Acre in anticipation of the arrival of a vanguard of the Third Crusade in 1191 (with a primary goal of reclaiming Jerusalem), Guy of Lusignan (c. 1150 – 18 July 1194) a Poitevin knight, son of Hugh VIII of the Lusignan dynasty, departed Acre with a small fleet and landed at Limassol to seek support from Richard I of England, whose vassal he had been in Poitou. He swore fealty to King Richard, and had attended his wedding to Berengaria of Navarre. He participated in the campaign against Isaac Comnenus of Cyprus thus. In return for this aid, when Richard and his army arrived at Acre, Richard supported Guy entirely while Conrad naturally had the support of his kinsmen Philip II of France and Leopold V of Austria.
When Saladin invaded the kingdom and captured almost everything except the stronghold of Tyre, held by Conrad of Montferrat, Baldwin V's uncle; Guy, after his release from captivity, set had about besieging Acre; however, Sibylla, his wife and their two daughters died of disease in the camp in summer 1190. Despite this Guy continued to call himself King and demanded to be recognised thus, although Isabella, Amalrics daughter, was de jure Queen. Her supporters, notably her mother Maria and Balian of Ibelin, realised that Isabella needed a suitable king – who at the time was not her current husband. This situation was not without precedent: Isabella's father had been forced to divorce his first wife in order to succeed to the throne, and Sibylla had been pressed – but had refused – to have Guy annulled. Humphrey of Toron, whom Isabella liked very much, having practically grown up with him, had no great desire to be king. He had let down her cause in 1186, and was still a staunch supporter of Guy. He was more of a diplomat than a warrior, and even the Itinerarium Peregrinorum, which was highly sympathetic to him, suggests he was slightly effeminate. In autumn 1190, Maria and Balian abducted Isabella from Humphrey, and forced her to consent to an annulment because she had been under-age at the time of her marriage, and had been coerced by her half-brother, Baldwin IV. They intended to marry her to the ambitious Conrad, who was Baldwin V's nearest male kinsman, and had already proved himself capable politically and militarily.
After much political pressure, and a challenge to a trial by combat by Guy III of Senlis (which he refused), Humphrey consented to an ecclesiastical annulment by Ubaldo Lanfranchi, Archbishop of Pisa, who was Papal legate, and Philip of Dreux, bishop of Beauvais, who was a second-cousin of Conrad. Philip married Conrad and Isabella on 24 November, despite objections that the marriage was canonically incestuous (Isabella's half-sister Sibylla having been married to Conrad's older brother). Some modern popular writers have suggested this was a grim fate for the young Queen, to be married off to a "grizzled old warrior" who had twice been married before. However, Conrad, then about 45, was an intelligent, well-educated, handsome man of great personal courage and vitality. She compensated Humphrey by restoring to him his title to Toron, Chastel Neuf and related estates, which had been taken into the Royal domain on their marriage, before returning to Tyre with her new husband.
By virtue of his marriage to Isabella, Conrad became de jure uxoris King of Jerusalem. However, for seventeen months Guy of Lusignan, despite the death of Sibylla, continued his claim. Eventually, after Philip's departure, Conrad's kingship was confirmed by election in April 1192, which Guy accepted.
The news was brought to the couple in Tyre by Count Henry II of Champagne, the nephew of both the Kings of England and of France, who then returned to Acre. Only a few days later, on 28 April, Isabella and her ladies were late for dinner through lingering at the hammam. Conrad called on the Bishop of Beauvais, hoping to dine with him, but finding the bishop had already dined, set off back to the palace. On the way, he was set upon in the street and stabbed by Hashshashin. He died of his wounds that same day. Isabella was already known to be carrying their first child – Maria of Montferrat, who later succeeded her mother as Queen Regnant (see the Old French Continuation of William of Tyre, the Brevis Regni Hierosolymitani Historia in the Annals of Genoa, and the Muslim chronicler Imad ad-Din al-Isfahani). When Conrad had denied sanctuary to Sibylla and Guy, (Guy was imprisoned in Damascus prior), Guy and Conrads conflict continued throughout the siege of Acre, although it was not his character to assassinate a alternative claimant to the throne, in fact Guy had gallantly saved Conrad's life when he was surrounded by the enemy during the Acre seige. Richard, Philip, and Leopold had however quarrelled over the spoils of the victory from the claiming of Acre. When Leopold's Ducal flag were raised in the city by Leopold's cousin Conrad of Montferrat, Richard removed Leopold's colours. In the struggle for the Kingship of Jerusalem, he had proclaimed Guy would continue to rule but that Conrad would receive the crown upon his death. Frustrated with Richard (and in Philip's case, in poor health), Philip and Leopold had taken their armies and left the Holy Land. Philip also left 10,000 French crusaders and 5,000 silver marks to pay them.
The Crusader campaign continued based largely at Ascalon, when both Saladin and Richard made a political treaty, whereby in exchange for access to Ascalon, along with a three-year truce Christian access to Jerusalem was permitted. After the agreement was signed on September 2, 1192, Richard departed Israel on plan with Robert de Sablé the Templar grand master(a order founded by Hugh de Payens in 1119), for a safe return, though foiled by bad weather, on land break in December 1192/93 Leopold captured Richard, imprisioning him in Weitra Castle. Accused of his cousin Conrads murder, a ransom 2–3 times the annual income for the English Crown under Richard (65,000 pounds of silver) was paid by England. Eleanor of Aquitaine worked to raise the ransom meanwhile Duke Leopold and Henry VI were excommunicated by Pope Celestine III for their crime. Even though John, Richard's brother, and King Philip of France offered 80,000 marks for his continued detainment, after being held by Henry VI of Hohenstaufen at Trifels Castle for three weeks in March 1193, and over three months altogether Richard and Henry ceremoniously reconciled at the Hoftag in Speyer during Holy Week 1194. Henry VI had been aggrieved by the support the Plantagenets (Angevin Empire) had given to the family of Henry the Lion, and by Richard's recognition of Tancred in Sicily. Also Henry needed money to raise an army and assert his rights over southern Italy which he promptly conquered.
Isabella while pregnant had remained Queen and married Richard's nephew Henry II of Champagne; when he died in 1197, Isabella married Amalric II (known as Aimery he was Guy's brother and also the son of Hugh VIII of Lusignan who had himself campaigned in the Holy Land since the 1160s - In 1198, at the end of the Crusade of 1197, Aimery was able to procure a five years' truce with the Muslims, owing to the struggle between Saladin's brothers and his sons for the inheritance of his territories. The truce was disturbed by raids on both sides, but in 1204 it was renewed for six years) Guy was compensated for the dispossession of his crown by being given lordship of Cyprus in 1192, which Richard had annexed from the Byzantine Empire en route to the Levant. Isabella Queen regnant of Jerusalem from 1190/1192 until her death, by her four marriages, Isabella was successively Lady of Toron, Marchioness of Montferrat, Countess of Champagne and Queen of Cyprus.
She was the daughter of Amalric I of Jerusalem and his second wife Maria Comnena, Amalric of Jerusalem (also Amaury) (1136 – 11 July 1174) who was King of Jerusalem 1163–1174, and Count of Jaffa and Ascalon. Amalric was the second son of Melisende of Jerusalem and Fulk of Jerusalem, and succeeded his older brother Baldwin III King of Jerusalem at the time of Saladins invasion. When Baldwin IV finally succumbed to his leprosy in 1185 dying in Jerusalem in spring 1185. Baldwin V became King then, but he was a sickly child and died within a year. Guy went with Sibylla to Jerusalem for his stepson's funeral in 1186, along with an armed escort, with which he garrisoned the city. Raymond III, who wanted to protect his own influence and his new political ally, the dowager queen Maria Comnena, was making arrangements to summon the Haute Cour when Sibylla was crowned queen by Patriarch Eraclius. Raynald of Châtillon gained popular support for Sibylla by affirming that she was "li plus apareissanz et plus dreis heis dou rouame" ("the most evident and rightful heir of the kingdom"). With the clear support of the church Sibylla was undisputed sovereign.
However, before she was crowned she agreed with oppositional court members that she would annul her marriage with Guy to please them, as long as she would be given free choice in her next husband. The leaders of the Haute Cour agreed, and Sibylla was crowned thereafter as Queen regnant. Taking her choice as husband, to the astonishment of the rival court faction, she remarried Guy, who became King in August 1186. The Queen removed the crown from her head and handed it to Guy, permitting him to crown himself, at the Church of the Holy Sepulchre in Jerusalem, in September 1186. As Hamilton writes, "there could be no doubt after the ceremony that Guy only held the crown matrimonial". Sibylla's half-sister Isabella and her husband Humphrey IV of Toron were Raymond III and the Ibelins' choice for the throne. As Sibylla's parents marriage had been annulled and both she and Baldwin had been legitimised by the church, Isabella was seen by many as the legal heiress. However, Humphrey would not assert his wife's claim, and he disassociated himself from them, swearing fealty instead to Sibylla. Humphrey would become one of King Guy's (1186 to 1192) closest allies in his Kingdom.