Page "History of Toulouse" Paragraph 31

Following these events, Charles the Bald in 845 signed a treaty with King Pippin II of Aquitaine whereby he recognized him as king of Aquitaine, in exchange of which Pippin II was relinquishing the northern part of Aquitaine ( county of Poitiers ) to Charles the Bald.

However, the Aquitanians grew very unhappy with their king Pippin II, perhaps for his friendliness towards the Vikings who inflicted terrible damage on the population, and so in 848 they called Charles the Bald to topple Pippin II.

In 849 Charles the Bald was south again, and he was handed over the capital of Aquitaine, Toulouse, by Frédelon, the count of Toulouse recently appointed by Pippin II.

Charles the Bald then officially confirmed Frédelon as count of Toulouse.

Soon the whole of Aquitaine was submitting to Charles the Bald, and in 852, Pippin II was made prisoner by the Basques and handed over to his uncle Charles the Bald who put him in a monastery.