Which Egyptian city did Louis IX capture in 1249 during the Seventh Crusade? Damietta. The strategically placed port on the Nile Delta became the first major objective of Louis IX’s Egyptian campaign and a vital base for his planned advance toward Cairo and Jerusalem.
Louis landed near Damietta in June 1249. On 5 June, the crusaders fought their way ashore, but the city’s defenders and population withdrew after the Muslim commander Fakhr al-Din evacuated the garrison. Damietta fell to Louis on 6 June with comparatively little resistance.
The capture seemed promising because Damietta controlled access to the Nile and held stores of food and military equipment. However, seasonal flooding trapped the crusaders for months, while heat, disease, and shortages weakened the army. Louis eventually advanced south, but his forces were defeated at Mansurah in 1250, and he was captured soon afterward.
Mansurah was therefore a later battlefield, not the city captured in 1249. Alexandria and Cairo were also important Egyptian centers, but neither is the canonical answer to this question.