Leper King Baldwin IV of Jerusalem
Life and Legacy

Life and Legacy of the Leper King

The Leper King was Baldwin IV, king of Jerusalem from 1174 to 1185. He was crowned on 15 July 1174, when he was “barely thirteen years old”, and he had leprosy for his whole reign. At sixteen he defeated Saladin at Montgisard. By 1183 he was blind and could no longer use his hands or feet, and he died in 1185, aged 23 or 24. Two years after his death, Jerusalem fell to Saladin.

Most of what we know about him comes from one man who knew him well: William of Tyre, his tutor, later chancellor of the kingdom and archbishop of Tyre, whose chronicle stops early in 1184. That gives us an unusually close witness. It also means the main witness was a friend with his own politics, which is worth keeping in mind below.

How the Leprosy Was Found

William took charge of the prince’s education around 1170, when the boy was about nine. One day Baldwin was playing with other noble boys, and they began, “as playful boys often do, to pinch each others’ arms and hands with their nails.” The others cried out. Baldwin did not. When William questioned him, he found that the boy’s “right arm and hand were partially numb, so that he did not feel pinching or even biting in the least.”

Physicians tried “repeated fomentations, oil rubs, and even poisonous remedies”, without result. As Baldwin reached his teens it became clear that he had leprosy. “The extremities and the face were especially attacked,” William writes, and yet the boy became “an excellent horseman”.

Was it really leprosy? In the Middle Ages the word covered several skin diseases, and some have suggested Baldwin had endemic syphilis instead. The medical historian Piers Mitchell weighed the symptoms William describes, above all the numbness and the destruction of the hands and feet, and concluded they fit lepromatous leprosy, the most severe form, better than endemic syphilis.

A Boy King and a Regent

Baldwin’s father, King Amaury, died in July 1174. On 15 July, “the fourth day after the death of his father”, Baldwin was consecrated and crowned in the Church of the Holy Sepulchre.

A thirteen-year-old could not rule alone. Raymond III, count of Tripoli, claimed the regency as the king’s next of kin, and from then on the kingdom’s politics turned on two questions: who governed while the king was ill, and who would succeed a sick king with no children.

Legacy and Impact

Montgisard, 25 November 1177. Saladin’s army was raiding the kingdom while Baldwin was at Ascalon. The king, then sixteen, led his forces out along the coast, joined by the Templars from Gaza, and met Saladin before all of his scattered raiders could regroup. William names the lords with the king, among them Reynald of Châtillon and the brothers Baldwin of Ramla and Balian of Ibelin, and says their men, “including all ranks and conditions, were barely three hundred and seventy-five.” After asking around, he put Saladin’s force at twenty-six thousand light cavalry. Those are William’s figures, and chroniclers’ numbers deserve caution. William also says the king led out “all his forces, both cavalry and infantry”, so the whole Christian army was larger than those 375. By his account Saladin’s lines broke and the Christians chased them “for twelve miles and more”.

Two details complete the picture. William was probably with the army, so this is close to an eyewitness account. And the king had appointed Reynald of Châtillon regent and commander in chief a few months earlier; William’s modern translators call Reynald “the real commander” of the victory. Baldwin led, and he was there, but a sixteen-year-old king did not win the battle alone.

How he governed

Baldwin’s eleven-year reign was held together by alliances, building and marriage politics as much as by battle.

• He looked for allies abroad. In 1177 the kingdom had a joint campaign against Egypt “arranged with the emperor of Constantinople”, Manuel I Komnenos. Count Philip of Flanders, whom the barons asked to lead it, refused to go to Egypt.
• He fortified the frontier. In October 1178 he began a castle at Jacob’s Ford, beyond the Jordan and ten miles from Banyas, built “within six months”. Saladin took it in 1179.
• He managed the succession. In April 1180 he married his sister Sibylla to Guy of Lusignan and made Guy count of Jaffa.
• He changed course when it failed. In 1183, with the leprosy much worse, he named Guy regent. By November he had taken the government back, and he had Sibylla’s son from her first marriage, a boy “scarcely five years old”, crowned as co-king Baldwin V, cutting Guy out of the succession.

“Kingdom of Heaven” (2005): what the film gets right, and what it invents

Baldwin IV is a central character in Ridley Scott’s Kingdom of Heaven, written by William Monahan, in which he is played, masked and uncredited, by Edward Norton. The film is worth watching. Several of its most famous touches are its own.

• The silver mask. Neither of the two main chronicles of his reign, William of Tyre and the chronicle attributed to Ernoul, mentions a mask. William describes a face and hands attacked by the disease.
• “A king may move a man, a father may claim a son…” This speech is film dialogue, spoken by Baldwin to Balian. It is not a medieval quotation.
• “It is a kingdom of conscience, or nothing.” In the film this is Balian’s line, not Baldwin’s.
• Balian of Ibelin. In the film he is a blacksmith. The real Balian was a baron of the kingdom and the brother of Baldwin of Ramla. He fought at Montgisard in 1177, and in 1187 he led the defence of Jerusalem.
• What the film gets right is the shape of it: a young king holding a fragile kingdom together while his body failed, with rival factions already fighting over what came next.

How historians judge the reign

There are two main ways to read his reign, and they are a matter of interpretation rather than fact.

The traditional view, as the historian Bernard Hamilton summarises it, sees the reign as “a period of decline” in which the king’s illness let “unsuitable men” take power and make the wrong decisions. Hamilton’s book The Leper King and His Heirs (Cambridge University Press, 2000) argues the opposite: that peace with Saladin was never a real option, that Baldwin “was an excellent battle leader”, and that he “had to remain king in order to hold factions in check.” It is one historian’s argument, made at book length by a specialist, and the evidence above lets readers weigh both.

What does not survive William’s account is the popular picture of a figurehead. Even blind, it was Baldwin who, on the advice of his counsellors and his mother, took the government back from Guy and had Baldwin V crowned.

How it ended

Kerak, 1183. Late in 1183 Saladin besieged the castle of Kerak, beyond the Jordan, in the middle of a wedding: the young Humphrey of Toron was marrying the king’s younger sister, Isabella. The chronicle attributed to Ernoul adds that Humphrey’s mother sent Saladin bread, wine, oxen and sheep from the wedding feast, and that Saladin ordered his men not to attack the tower where the couple were staying. The king, blind by now, took the True Cross and marched to relieve the castle, placing Raymond of Tripoli in command of the army. Saladin withdrew after a siege that William puts at “an entire month”; the chronicle attributed to Ernoul says eight weeks (six in some manuscripts).

Neither William nor Ernoul says how he travelled; William simply says he “marched thither himself”. The historian Bernard Hamilton judges that he was “almost certainly too ill to ride, and would have had to be carried in a litter”, and later describes him being carried into battle “in a litter slung between two horses” when he went to the relief of Kerak in 1183 and again in 1184. William does record him being carried in a litter when he was ill in 1177.

The end. Baldwin died in 1185, and the exact day is uncertain. The medical historian Piers Mitchell gives 16 March 1185; Bernard Hamilton says only that he died “at some time before 16 May 1185”, “not quite twenty-four years old”. Baldwin V died the following year, and Guy of Lusignan became king. On 4 July 1187 Guy’s army was destroyed at Hattin, near Tiberias, and Guy was taken prisoner. Jerusalem surrendered to Saladin on 2 October 1187, after a defence led by Balian of Ibelin. Those who paid their ransom were escorted to Tyre, which was still in Christian hands, but the city Baldwin had ruled from was lost two years after his death.

What His Story Is Useful For

Baldwin’s story is often told as pure inspiration. It is more useful read carefully:

1. Separate the chronicle from the film. The mask, the speeches and the blacksmith are Hollywood’s. The pinching game, Montgisard and Kerak are William’s. When you meet a moving line attributed to a medieval king, check whether it comes from a screenplay.
2. Ask who the witness was. William was devoted to his pupil and opposed to some of the men around him. His translators point out places where his opinions follow his politics. A single close witness is valuable, and it is still a single witness.
3. Look at what he built around himself. A king who did not expect to live long spent his reign on regents, alliances, castles and a successor. The lasting interest of the reign is less his courage, which is real, than the arrangements he made for a future he would not see.

Checked September 2026.

Sources

• William of Tyre, A History of Deeds Done Beyond the Sea, translated by Emily Atwater Babcock and A. C. Krey (Columbia University Press, 1943), Books XXI–XXII. Internet Archive.
• Chronique d’Ernoul et de Bernard le Trésorier, ed. L. de Mas Latrie (Paris, 1871). Internet Archive.
• Bahā’ al-Dīn Ibn Shaddād, The Life of Saladin, translated by C. W. Wilson (Palestine Pilgrims’ Text Society, 1897). Internet Archive.
• Piers D. Mitchell, “Leprosy and the case of King Baldwin IV of Jerusalem”, International Journal of Leprosy 61 (2), 1993, pp. 283–291. Journal page.
• Bernard Hamilton, The Leper King and His Heirs (Cambridge University Press, 2000), pp. 196, 210, 241. Publisher’s page.
• Kingdom of Heaven (2005), scene transcripts: “A king may move a man” and “It is a kingdom of conscience, or nothing”.
• 3DVF, He isn’t even in the credits, so who plays Kingdom of Heaven’s masked king? (24 June 2026).