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September 11, 2026Short & citedBlog
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Civic Brief • Monarch

King Baldwin

“King Baldwin” most commonly refers to one of the medieval kings of Jerusalem from the House of Boulogne, especially Baldwin I and Baldwin IV.

Updated September 11, 20261 min readCited sources

“King Baldwin” most commonly refers to one of the medieval kings of Jerusalem from the House of Boulogne, especially Baldwin I and Baldwin IV.

What it is

The name “King Baldwin” covers several rulers of the Crusader Kingdom of Jerusalem, most notably Baldwin I (reigned 1100–1118), who founded and expanded the kingdom after the First Crusade, and Baldwin IV (reigned 1174–1185), known as the “Leper King” for ruling despite leprosy. Baldwin III (reigned 1143–1163) also strengthened the kingdom during the mid-12th century.

Why it matters

The Baldwin kings were central to the history of the Crusader states in the Levant. Baldwin I consolidated the new kingdom, Baldwin III expanded its borders, and Baldwin IV famously resisted Saladin’s growing power while managing his own debilitating illness. Their reigns shaped military, political, and territorial developments in the region.

Key details

Baldwin I became king in 1100 after the First Crusade and is linked to founding the Kingdom of Jerusalem. Baldwin IV became king at age 13 and ruled until 1185, earning his nickname from leprosy. The House of Boulogne dynasty produced these rulers, whose legacy remains a major part of Crusader history.

In short

  • “King Baldwin” refers to several medieval kings of Jerusalem, not one person.
  • Baldwin I founded and expanded the Kingdom of Jerusalem after the First Crusade.
  • Baldwin IV, the “Leper King,” ruled from 1174 to 1185 despite leprosy.
  • Their reigns were pivotal in the Crusader states’ history.

Quick questions

Who was King Baldwin?
“King Baldwin” usually refers to one of several medieval kings of Jerusalem, especially Baldwin I or Baldwin IV.
Why was Baldwin IV called the Leper King?
Baldwin IV was called the “Leper King” because he suffered from leprosy during his reign.
Was there more than one King Baldwin of Jerusalem?
Yes. The best-known rulers with this name include Baldwin I, Baldwin III, and Baldwin IV.

Sources

  1. Encyclopaedia Britannica — https://www.britannica.com/biography/Baldwin-I-king-of-Jerusalem
    Supports: Baldwin I as king of Jerusalem from 1100 to 1118; his role in expanding and securing the kingdom.
  2. Encyclopaedia Britannica — https://www.britannica.com/biography/Baldwin-IV-king-of-Jerusalem
    Supports: Baldwin IV as king of Jerusalem from 1174 to 1185 and his nickname as the Leper King.
  3. Wikipedia — https://www.wikiwand.com/en/articles/Baldwin_III_of_Jerusalem
    Supports: Baldwin III as king of Jerusalem from 1143 to 1163 and his significance in expanding the kingdom.
  4. Encyclopedia.com — https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/baldwin-king-jerusalem
    Supports: Several kings of Jerusalem named Baldwin, including Baldwin I and Baldwin III.
  5. Wikipedia — https://en.wikipedia.org/wiki/Baldwin_IV_of_Jerusalem
    Supports: Baldwin IV became king at age thirteen, had leprosy, and reigned until 1185.