[9] There was some resistance to his accession as count, which was suppressed with the help of his mother Blanche of Castile who was acting as regent in the absence of Louis IX.

[10] In 1252, on the death of his mother, Blanche of Castile, Alphonse was joint regent with Charles of Anjou until the return of Louis IX.

During that time he took a great part in the campaigns and negotiations which led to the Treaty of Paris in 1259, under which King Henry III of England recognized his loss of continental territory to France (including Normandy, Maine, Anjou, and Poitou) in exchange for France withdrawing its support for English rebels.

[13] When Louis IX formed the Eighth Crusade, Alphonse again raised a large sum of money and accompanied his brother.

However, Joan was the only surviving child and heiress of Raymond VII, Count of Toulouse, Duke of Narbonne, and Marquis of Provence, so under Provençal and French law, the lands should have gone to her nearest male relative.

[10] One specific bequest in Alphonse's will, giving his wife's lands in the Comtat Venaissin to the Holy See, was allowed, and it became a papal territory, a status which it retained until 1791.