Charles suddenly learned that his mother Judith was on the point of being besieged in Poitiers by the Aquitanians; and, in spite of the friendly protestations sent to him by Lothaire, it was not long before he discovered the plot formed against him.

He was not wanting in shrewdness or energy; and, having first provided for his mother's safety, he set about forming an alliance, in the cause of their common interests, with his other brother, Louis the Germanic, who was equally in danger from the ambition of Lothaire.

The historians of the period do not say what negotiator was employed by Charles on this distant and delicate mission; but several circumstances indicate that the Empress Judith herself undertook it; that she went in quest of the king of Bavaria; and that it was she who, with her accustomed grace and address, determined him to make common cause with his younger against their eldest brother.

Divers incidents retarded for a whole year the outburst of this family plot, and of the war of which it was the precursor.

The position of the young King Charles appeared for some time a very bad one; but "certain chieftains," says the historian Nithard, "faithful to his mother and to him, and having nothing more to lose than life or limb, chose rather to die gloriously than to betray their king." The arrival of Louis the Germanic with his troops helped to swell the forces and increase the confidence of Charles; and it was on the 21st of June, 841, exactly a year after the death of Louis the Debonnair, that the two armies, that of Lothaire and Pepin on the one side, and that of Charles the Bald and Louis the Germanic on the other, stood face to face in the neighborhood of the village of Fontenailles, six leagues from Auxerre, on the rivulet of Audries.