Leper King Baldwin IV of Jerusalem: Life and Legacy

Start hereAt sixteen he led all his forces out against Saladin, and Saladin's lines broke at Montgisard. Yet his tutor's modern translators call another man, Reynald of Châtillon, "the real commander" of that victory. How much of the legend was his?

01Life and Legacy of the Leper King

Fact	Detail
Reign	King of Jerusalem, 1174 to 1185
Crowned	15 July 1174, “barely thirteen years old”
Illness	Leprosy: first signs at about nine, clear in his teens; blind by 1183
Died	1185, aged 23 or 24; the exact day is uncertain
Key victory	Beating Saladin at Montgisard in 1177
Main witness	William of Tyre, his tutor

Most of what we know about him comes from one man who knew him well. William of Tyre was his tutor, later chancellor of the kingdom and archbishop of Tyre, and his 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. That is worth keeping in mind as you read on.

02How the Leprosy Was Found

The first sign showed up during a game. William took charge of the prince’s education around 1170, when the boy was about nine.

One day Baldwin and some other noble boys were pinching each other’s arms and hands with their nails, as boys at play often do. 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 warm compresses, oil rubs and even poisonous remedies, without result. As Baldwin reached his teens, it became clear that he had leprosy.

William writes that it attacked his hands, feet and face most of all. Even so, the boy became an excellent rider.

Was it really leprosy? Some of what the Middle Ages called leprosy may have been endemic syphilis, and some have suggested Baldwin had endemic syphilis instead.

The medical historian Piers Mitchell weighed the symptoms William describes, among them the numbness and the destruction of the hands and feet. He concluded they fit lepromatous leprosy, the most severe form, better than endemic syphilis.

03A Boy King and a Regent

Baldwin’s father, King Amaury (also called Amalric), died in July 1174. On 15 July, four days after his father’s death, 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, the right to govern for the boy, as the king’s next of kin.

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?

04Montgisard, 1177

On 25 November 1177 the teenage king defeated Saladin at Montgisard, though the numbers and the credit both need care.

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. Their men, he says, numbered barely 375, of all ranks and conditions.

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 more than twelve miles.

Two details complete the picture. William was probably with the army, so this is close to an eyewitness account.

A few months earlier, the king had appointed Reynald of Châtillon regent and commander in chief. 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.

05How 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 planned with the Byzantine emperor, 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. It was 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. He had Sibylla’s son from her first marriage, a boy scarcely five years old, crowned as co-king Baldwin V. That cut Guy out of the succession.

06How it ended

By 1183 he was blind and could no longer use his hands or feet.

Kerak, 1183. Late in 1183 Saladin besieged the castle of Kerak, beyond the Jordan, at the time 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. It also says 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, or 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”. Later in the book, he describes Baldwin carried into battle in a litter between two horses when he went to relieve 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 some time before 16 May 1185, when he was not quite twenty-four.

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. Baha ad-Din says those who paid their ransom were escorted to Tyre, which was still in Christian hands. In the chronicle attributed to Ernoul, the escorted columns go north to the county of Tripoli.

So the city Baldwin had ruled from was lost, two years after his death.

07How 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 this view, the king’s illness let unsuitable men take power and make the wrong decisions.

Hamilton’s own book, The Leper King and His Heirs (2000), argues the opposite. In his view, peace with Saladin was never a real option, and Baldwin “was an excellent battle leader”. He also argues that Baldwin had to remain king to hold the factions in check.

It is one historian’s argument, made at book length by a specialist. The evidence on this page lets you weigh both.

Given how ill he was, it is easy to picture him as a figurehead. William’s account shows more than that. 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.

The witness matters here too. 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.

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

If you know him from Ridley Scott’s film Kingdom of Heaven (2005), treat it as a drama. It is not a reliable history. Its silver mask, its famous speeches and its blacksmith Balian are the film’s own, as the list below shows.

Baldwin IV is a central character in the film, written by William Monahan. Edward Norton plays him, masked and uncredited. The film is worth watching.

• 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 holds a fragile kingdom together while his body fails, and rival factions are already fighting over what comes next.

The mask	Film: a silver mask. Record: neither William of Tyre nor the chronicle attributed to Ernoul mentions one.
The speech	Film: “A king may move a man…”. Record: film dialogue, not a medieval quotation.
The conscience line	Film: Balian’s line, not Baldwin’s.
Balian	Film: a blacksmith. Record: a baron, brother of Baldwin of Ramla, who fought at Montgisard in 1177.

Kingdom of Heaven (2005), directed by Ridley Scott and written by William Monahan.

09His legacy

Baldwin’s courage is real. Read closely, the record shows something more.

A king who did not expect to live long spent his reign on regents, alliances, castles and a successor. In our reading, the lasting interest of the reign is less his courage than the arrangements he made for a future he would not see.

Chronicle or film?Check whether a moving line comes from a screenplay

Who was the witness?One close witness is valuable, and still one witness

What did he build?Regents, alliances, castles and a successor

10Quick answers

11Use this

12Quick quiz

How we checked this · Last checked October 2026

• William of Tyre's chronicle (Babcock and Krey's 1943 translation) and the chronicle attributed to Ernoul (1871 edition) were read in their Internet Archive scans; Baha ad-Din in the 1897 Palestine Pilgrims' Text Society translation.
• That the chronicles mention no silver mask rests on full-text searches of William of Tyre and Ernoul; that the two film speeches are not medieval, on searches of the same texts.
• Bernard Hamilton's The Leper King and His Heirs was checked against its printed pages (196, 210, 241); no copy can be linked, so the Sources list links the publisher's page.
• The litter at Kerak is Hamilton's inference. Neither William nor Ernoul says how the king travelled there.
• Ernoul's account of where the escorted columns went is in Old French; the English rendering is ours.

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13Sources