1239–1241 · Acre, Gaza and Ascalon
Barons' Crusade
The crusade of 1239–1241, led by Theobald IV, king of Navarre and count of Champagne, and then by Richard, earl of Cornwall, suffered a heavy defeat at Gaza. But by exploiting rivalry among the Ayyubid rulers, the leaders made treaties that extended the Kingdom of Jerusalem's borders to a degree not seen since 1187.

RESEARCH DOSSIER
Historical analysis of the event
Background
The Treaty of Jaffa of 1229 was due to expire in 1239. Pope Gregory IX called for a new expedition. French nobles, including King Theobald of Navarre, headed East with a large army. On the Ayyubid side, after al-Kamil's death in 1238, a bitter rivalry had begun among the relatives ruling Egypt and Damascus.
Course of events
Theobald reached Acre in September 1239. In November 1239 a group of French barons, despite Theobald's warnings, attacked Egyptian forces near Gaza and suffered a heavy defeat: Count Henry of Bar was killed and Amaury de Montfort captured. In December 1239 al-Nasir Dawud, lord of Kerak, entered Jerusalem and demolished the city's fortifications.
Theobald came to terms with al-Salih Isma'il of Damascus and recovered castles such as Beaufort and Safed. Richard of Cornwall, arriving in October 1240, had Ascalon fortified and in 1241 made a treaty with the Egyptian sultan al-Salih Ayyub. This treaty confirmed the earlier gains and freed those captured at Gaza.
Outcome and significance
At the end of the crusade the Kingdom of Jerusalem reached its greatest extent since 1187, including Jerusalem, much of Galilee and Ascalon. But these gains rested not on military strength but on Ayyubid rivalry and temporary treaties.
Indeed, in 1244 Egypt's Khwarazmian allies took Jerusalem and the same year the Frankish army was destroyed at La Forbie; most of these gains were soon lost.
Sources and debates
The continuations of Ernoul and the Rothelin continuation give the Latin view; Matthew Paris reports Richard's activities from the English side. Ibn Wasil and Sibt ibn al-Jawzi describe relations among the Ayyubids and the treaties. The boundaries and castle lists of the treaties differ between sources.
Dates, places and figures in this record compare the principal narrative sources with modern scholarship. Where the sources disagree this is stated in the text; for a thesis or publication, consult the relevant edition and page reference.