Preparations had been underway in France for a Crusade (the Seventh), and Charles joined his brother along with their other brothers, Robert and Alphonse. They did not depart until til 25 August 1248.
While Charles was away, the cities of Arles, Avignon, and Marseilles joined their military forces in an alliance. They chose a leader of their own, Barral of Baux, who had helped negotiate a conflict earlier between Savoy and Provence. Barral's army helped Charles save Beatrice of Provence from the forces of James I of Aragon that had surrounded her, and Barral's army helped guard the wedding of Beatrice and Charles.
Barral saw Charles' disrespect for the local nobles and was willing to join the rebellion against him. Charles' mother-in-law, Beatrice of Savoy, supported the rebel alliance. But more on that later.
The Seventh Crusade did not go well. Louis was very keen on it, but no one else in Europe was interested or free enough of other concerns to join. The French had to go it alone. They invaded Egypt in early June 1249, capturing Damietta and intending to invade Cairo in November. Charles' older brother Robert was killed in battle in February 1250 (see illustration). While retreating from Egypt, the remaining brothers were captured. Their ransom was the return of Damietta and the payment of 800,000 bezants.
While the army sailed to Acre, Charles showed his callow nature by spending his time gambling while Louis was mourning their brother.
Returning to Provence, Charles continued to have his people make an account of all the towns and his possessions and claims. His decisions to increase his revenue and make demands of towns came up against the rebellion. One particular decision that rankled was the salt tax. We'll learn more tomorrow.