Having in 842 crushed a rising in Saxony, he compelled the Abotrites to own his authority, and undertook campaigns against the Bohemians, the Moravians and other tribes, but was not very successful in freeing his shores from the ravages of Danish pirates. At his instance synods and assemblies were held where laws were decreed for the better government of church and state. In 853 and the following years Louis made more than one attempt to secure the throne of Aquitaine, which the people of that country offered him in their disgust with the cruel misrule of Charles the Bald. But though he met with sufficient success to encourage him to issue a charter in 858, dated "the first year of the reign in West Francia," treachery and desertion in his army, and the loyalty to Charles of the Aquitanian bishops brought about the failure of the enterprise, which Louis renounced by a treaty signed at Coblenz on the 7th of June 860. In 855 the emperor Lothair died, and was succeeded in Italy by his eldest son Louis II., and in the northern part of his kingdom by his second son, Lothair. The comparative weakness of these kingdoms, together with the disorder caused by the matrimonial troubles of Lothair, afforded a suitable opening for the intrigues of Louis and Charles the Bald, whose interest was increased by the fact that both their nephews were without male issue. Louis supported Lothair in his efforts to divorce his wife Teutberga, for which he received a promise of Alsace, while Charles opposed the divorce. But in 865 Louis and Charles meeting near Toul, renewed the peace of Coblenz, and doubtless discussed the possibility of dividing Lothair's kingdom. In 868 at Metz they agreed definitely to a partition; but when Lothair died in 869, Louis was lying seriously ill, and his armies were engaged with the Moravians. Charles the Bald accordingly seized the whole kingdom; but Louis, having recovered, compelled him by a threat of war to agree to the treaty of Mersen, which divided it between the claimants. The later years of Louis were troubled by risings on the part of his sons, the eldest of whom, Carloman, revolted in 861 and again two years later; an example that was followed by the second son Louis, who in a further rising was joined by his brother Charles. A report that the emperor Louis II. was dead led to peace between father and sons. The emperor, however, was not dead, but a prisoner; and as he was not only the nephew, but also the son-in-law of Louis, that monarch hoped to secure both the imperial dignity and the Italian kingdom for his son Carloman. Meeting his daughter Engelberga, the wife of Louis II., at Trent in 872, Louis made an alliance with her against Charles the Bald, and in 874 visited Italy doubtless on the same errand. The emperor, having named Carloman as his successor, died in August 875, but Charles the Bald reached Italy before his rival, and by persuading Carloman, when he did cross the Alps, to return, secured the imperial crown.