King Louis VIII of France besieged the town of Avignon, which lay within the Holy Roman Empire, from 10 June until 9 September, when it surrendered on terms.

He advanced to Lyon and then down the Rhône Valley on the left bank (the imperial side), his ultimate goal being the submission of Count Raymond VII of Toulouse, who as Marquis of Provence also held lordship over Avignon.

It was wealthy, possessing a full double wall with two large gate towers (named Quiquenparle and Quiquengrogne).

They agreed not to impede the travel of Louis's baggage down the Rhône, and to allow him to cross the stone bridge of Saint-Bénézet (completed in 1188[2]) with a small retinue.

[11] According to one rumour popular at the time, the Avignonese intended to kill Louis and the papal legate while they were passing through the city.

[13] The sole contemporary source to blame Louis for the break with Avignon is Roger of Wendover, who accuses the king of planning all along to attack the city.

[15] On 9 June, in a letter to Avignon's suzerain, the Emperor Frederick II, the French barons cited this incident, as well as the city's failure to supply the agreed upon number of hostages of suitable rank, as justification for his siege.

[16] The siege train he had moved down the Rhône on barges contained petraries, including trebuchets, and the walls of Avignon were bombarded continuously on all sides to little effect.

[4] Supporters of Raymond VII harried Louis's foragers and fought a scorched earth campaign, resulting in food shortages among the besiegers as well.

[15][18] Count Guy II of Saint-Pol led the assault, but the attackers received heavy fire from the towers and were repulsed.

[18] The Chronicle of Tours blames the failure of the assault on the treachery of Count Theobald IV of Champagne and Duke Peter I of Brittany.

The city agreed to pay Louis an indemnity of 6,000 marks (a rather small sum), to fund the construction of a royal fortress beside the abbey of Saint-André on the French side of the river and to cover the costs of sending 30 crusaders to Outremer, the last so as to expurgate the charge of heresy.

On 9 September, the gates were opened and Louis entered the city without violence while Cardinal Romanus granted absolution to the citizens.

[15][4] Two Occitan troubadours, Tomier and Palaizi, wrote a sirventes on the eve of the siege, bemoaning the emperor's lack of action and criticizing the diversion of crusading from its proper goal, the recovery of the Holy Sepulchre.

[5] Their refrain is "Let us be firm my lords, and let us count on powerful support": And although Frederick, the ruler of Germany, tolerates Louis unpicking his empire, the king from beyond Brittany will be most upset by it.

[5] Nicholas of Bray wrote an epic in Latin on Louis's military accomplishments, chiefly the sieges of La Rochelle (1224) and Avignon.

[20] He offers a vivid eyewitness description of the assault led by the count of Saint-Pol: Arrows are falling more heavily than rain, causing injury and death on all sides.