Baldwin IV (1161–1185), known as the Leper King, was the king of Jerusalem from 1174 until his death in 1185. Baldwin ascended to the throne when he was thirteen despite having leprosy. He made several attempts to curb the increasing power of the Muslim ruler Saladin, though much of his life was marked by infighting amongst the kingdom's nobles. Throughout his reign, and especially at the end of his brief life, he was troubled by his succession, working to select a suitable heir to the throne and prevent a succession crisis. Choosing competent advisers, Baldwin ruled a thriving crusader state, protecting it from Saladin.
Baldwin's parents, King Amalric and Agnes of Courtenay, separated when Baldwin was two. At nine years old, he was sent to be educated by Archbishop William of Tyre. William noticed preliminary symptoms of leprosy, but Baldwin was only diagnosed after he succeeded his father as king. Thereafter, his hands and face became increasingly disfigured. He mastered horse riding despite gradually losing sensation in his extremities and fought in battles until his last years. First, Miles of Plancy ruled the kingdom in Baldwin's name, then Count Raymond III of Tripoli took over until Baldwin reached the age of majority in 1176. Baldwin became closer to his mother and uncle, Agnes and Joscelin of Courtenay, as Agnes returned to court. She had significant influence over her son, his court, and the politics of the kingdom during his reign.
As soon as he assumed government, Baldwin planned an invasion of Egypt, which fell through because of his vassals' uncooperativeness. Leprosy prevented Baldwin from marrying; he hoped to abdicate when his older sister, Sibylla, married William of Montferrat in 1176, but William died the next year. Saladin attacked the kingdom in 1177, but Baldwin and the nobleman Raynald of Châtillon repelled him at Montgisard, earning Baldwin fame. In 1180, to forestall a coup by Count Raymond III of Tripoli and Prince Bohemond III of Antioch, Baldwin had Sibylla marry Guy of Lusignan. However, Guy was opposed by a large fraction of the nobility, and soon permanently impaired his relationship with Baldwin through his insubordination. Although Baldwin wished to abdicate, the internal discord that followed forced him to remain on the throne, as only he was capable of uniting the quarreling nobility.
Baldwin again repelled Saladin in 1182 at the Battle of Le Forbelet, but leprosy rendered him near-incapable in 1183. After Guy's failure to lead, Baldwin disinherited him and had Sibylla's son, Baldwin V, crowned co-king before travelling in a litter to lift Saladin's Siege of Kerak. Because of their refusal to attend court, Baldwin failed to have Sibylla's marriage to Guy annulled and Guy's fief of Ascalon confiscated. In early 1185, he arranged for Raymond to rule as regent for Sibylla's son, dying of a fever before 16 May 1185. Two years after his death, his realm was destroyed by Saladin at the Battle of Hattin.
Baldwin was born in mid-1161, probably in Ascalon, but there is no official record of this. His parents were Amalric, then the count of Jaffa and Ascalon, and Agnes of Courtenay, making him the first prince whose parents were both born in the crusader states. Baldwin's godfather was his paternal uncle, King Baldwin III, who joked that his christening present was the Kingdom of Jerusalem. The kingdom and other crusader principalities, though surrounded by Arab Muslim states, were ruled by Franks, French-speaking Catholics who had arrived in the Levant from Western Europe and remained Western in culture. Baldwin III was young and recently married, making a nephew's accession seem unlikely; yet he died childless in 1163. Amalric was his heir, but the nobles of the kingdom were strongly opposed to Amalric's wife, Agnes; the historian Bernard Hamilton suggests that they were likely threatened by the prospect of her increased influence. The High Court forced Amalric to agree to an annulment of his marriage on the grounds of consanguinity in order to be accepted as king. Amalric succeeded in having his and Agnes's children, Sibylla and Baldwin, declared legitimate despite the annulment.
As Agnes remarried soon after the annulment (firstly to Hugh of Ibelin and then to Reynald of Sidon), Baldwin grew up without a mother; Hamilton surmises that she only saw Baldwin on public occasions. He also seldom saw his sister, Sibylla, who was raised in the Convent of Saint Lazarus by their grand-aunt Ioveta. When Baldwin was six, King Amalric married Maria Komnene, who was not close with Baldwin. Queen Maria was an ambitious woman who, in Hamilton's opinion, likely saw Baldwin as an obstacle to her progeny.
To ensure that his son and heir apparent received a good education, King Amalric sent the nine-year-old Baldwin to live with William of Tyre, a sophisticated and well-traveled cleric famed for his learning. William noticed that, unlike other noble children in the playground, Baldwin did not cry when pinched by his peers. After multiple reports of this, William realized that Baldwin could not feel pain in his right arm and grew worried about the boy's health. Amalric hired the Arab physician Abu Sulayman Dawud to treat Baldwin and his relative, Abul'Khair, to teach the boy horse riding, an essential skill for a Frankish nobleman. Having sensation in one hand, Baldwin learned to control his horse using solely his knees, and mastered riding despite this handicap. It was suspected that Baldwin had leprosy, but without visible symptoms, the physicians hesitated to diagnose him because of the stigma and limitations the boy would face; had such a diagnosis been made when he was a child, Baldwin might have been required by law to enter the Order of St Lazarus, a military order composed of affected knights and serjeants.
William said that Baldwin was precocious, determined, and optimistic in the face of his illness as an adolescent. He inherited his father's good looks, body shape, and manner of walking and expressing himself. Baldwin was a quick learner, but stuttered. He enjoyed listening to stories and history lessons. His memory was excellent, and he forgot neither kindness nor slights done to him by others.
In 1169, Amalric started seeking a mature husband for Sibylla so that a capable regent could rule the kingdom in case Amalric died while Baldwin was still a child. Count Stephen I of Sancerre accepted the offer. After his symptoms developed, Baldwin's accession became uncertain and attention turned to Sibylla and Stephen, but their match fell through. In June 1174, Amalric came down with dysentery, and died on 11 July 1174, leaving an underage heir as he had feared might happen.
Upon Amalric's death, the High Court convened to discuss the kingdom's succession. Though Baldwin was not diagnosed, Hamilton believed the High Court must have been aware of the royal physicians' suspicions that Baldwin had contracted leprosy. There was no viable alternative to succeed Amalric, however. Baldwin was the King's only son; Amalric's second marriage had produced two daughters, of which only Isabella survived infancy. Female succession was expressly allowed, but Sibylla was an unmarried adolescent, and Isabella was only two years old. The male candidates, Amalric's cousins Prince Bohemond III of Antioch, Baldwin of Antioch, and Count Raymond III of Tripoli, were politically unsuitable: Bohemond was bound to distant Antioch, Baldwin was in the service of Byzantine Emperor Manuel I Komnenos, and Raymond was virtually a stranger to the barons after nine years spent in Muslim captivity.
After three days of deliberation, Baldwin IV was unanimously chosen, with the expectation that a husband would be found for Sibylla to succeed him if he proved to be affected. The Latin patriarch of Jerusalem, Amalric of Nesle, crowned the young king in the Church of the Holy Sepulchre. Although medieval rulers were typically crowned on Sundays, 15 July 1174 was chosen for Baldwin's coronation instead as it was the 75th anniversary of the First Crusade's successful end to the siege of Jerusalem.