Alphonse of Poitiers

King Louis was accompanied on crusade by his brothers, Robert of Artois, Charles of Anjou and Alphonse of Poitiers.

Alphonse was the third oldest of the brothers (of those who survived childhood) and was given a sizeable amount of power and responsibility. He helped command against the English in the Saintonge War while still in his early twenties.

His mother was Blanche of Castile and this is represented in his arms.
Robert bore a label with the Castilian fortress on it and Charles initially had a bordure, also with the castle marked aroundit.
Blanche was seemingly a pretty formidable woman and made her mark through her sons. She was regent both in Louis's minority and again when he was abroad. He showed his respect to her in the decoration of the Sainte Chapelle in Paris- while the current decoration is a 19th century restoration it follows the likely original and for much of the surface the arms of France and Castile are scattered evenly across the walls. This chapel, incidentally, is well worth a visit. I went to watch a classical concert there and night which gives a chance to absorb the atmosphere and gaze at the decoration.

Alphonse's seal shows how the arms were portrayed on the caparison - France at the front, Castile at the back.

This layout, more than anything else, was the reason I wanted to paint the figure.

Alphonse was married to the heiress of the County of Toulouse and when his father in law died, Alphonse gained control of the county. This shows an interesting banner with the arms of Toulouse added to those of Alphonse, each portion of equal size. 

Alphonse seems to have been rather more level headed than his brother Robert. He fought well in the Seventh Crusade and returned to France to be co-regent when his mother died and Louis was still in the Holy Land. He took part in further campaigns to consolidate the gains from the English in France and then accompanied Louis on the Eighth Crusade to Tunis. This ended disastrously for the French but in a different way to the Seventh Crusade. This time, disease took many of the crusaders including Louis. Alphonse made it back to Europe where both he and his wife died.

One of his legacies was to leave the Holy See a grant of land which became the seat of the Avignon Papacy.