It seems apparent that the local magnates of Provence, ruling semiautonomously, had seen the impending danger coming from the north, and may have in turn called in the Muslim forces from bordering Septimania.
Arabs had occupied the city of Avignon in 734, after it had been surrendered to Yusuf ibn 'Abd al-Rahman al-Fihri, Umayyad governor of Narbonne, by Duke Maurontus of Provence.
According to the Continuations of Fredegar, Maurontus probably invited Yusuf into the city after forming an alliance with him against Martel.
The Chronicle of Moissac confirms that Yusuf's forces moved peacefully from Arab-held Septimania into Provence and entered Avignon without a fight.
In reaction, Martel had sent his brother Duke Childebrand south in 736, accompanied by fellow dukes and counts.
Childebrand had laid siege to Avignon, holding the field until his brother is ready to storm the city.
This battle is part of the campaigns of 736-737 during which Charles Martel for the second time keeps invading Muslim armies from Al-Andalus occupying further territory beyond the Pyrenees.
Unlike the invasion of 732-733, the Arabs come this time by sea, and force the Franks to come to them.
Notable at these battles is the use of heavy cavalry in addition to Martel's vaunted veteran Frankish infantry.
Though he has some catapults, the city of Avignon is largely taken by a simple, brutal, frontal assault using rams to smash through the gates, and ladders to scale the walls.
The city is burned to the ground following its capture.
The army then crosses the Rhône River into Septimania in order to lay siege to Narbonne.