In 850, Pepin, king of Aquitaine, and brother of Charles the Bald, came to an understanding with the Northmen who had ascended the Garonne, and were threatening Toulouse.

"They arrived under his guidance," says M.
Fauriel, "they laid siege to it, took it and plundered it, not halfwise, not hastily, as folks who feared to be surprised, but leisurely, with all security, by virtue of a treaty of alliance with one of the kings of the country." Throughout Aquitaine there was but one cry of indignation against Pepin, and the popularity of Charles was increased in proportion to all the horror inspired by the ineffable misdeed of his adversary.
Charles the Bald himself, if he did not ally himself, as Pepin did, with the invaders, took scarce any interest in the fate of the populations, and scarcely more trouble to protect them, for Hincmar, archbishop of Rheims, wrote to him in 859, "Many folks say that you are incessantly repeating that it is not for you to mix yourself up with these depredations and robberies, and that every one has but to defend himself as best he may." It were tedious to relate or even to enumerate all these incursions of the Northmen, with their monotonous incidents.

When their frequency and their general character have been notified, all has been done that is due to them from history.

However, there are three on which it may be worth while to dwell particularly, by reason of their grave historical consequences, as well as of the dramatic details which have been transmitted to us about them.
In the middle and during the last half of the ninth century, a chief of the Northmen, named Hastenc or Hastings, appeared several times over on the coasts and in the rivers of France, with numerous vessels and a following.

He had also with him, say the chronicles, a young Norwegian or Danish prince, Bieern, called Ironsides, whom he had educated, and who had preferred sharing the fortunes of his governor to living quietly with the king, his father.