They evacuated their posts and strong-holds in Wessex, and went down the Thames to London, which was in Mercia, and there commenced a new course of conquest and plunder, where they had no such powerful foe to oppose them.
Buthred was the king of Mercia.

He could not resist Hubba and his Danes alone, and he could not now have Alfred's assistance.

Alfred was censured very much at the time, and has been condemned often since, for having thus made a separate peace for himself and his own immediate dominions, and abandoned his natural allies and friends, the people of the other Saxon kingdoms.

To make a peace with savage and relentless pagans, on the express condition of leaving his fellow-Christian neighbors at their mercy, has been considered ungenerous, at least, if it was not unjust.

On the other hand, those who vindicate his conduct maintain that it was his duty to secure the peace and welfare of his own realm, leaving other sovereigns to take care of theirs; and that he would have done very wrong to sacrifice the property and lives of his own immediate subjects to a mere point of honor, when it was utterly out of his power to protect them and his neighbors too.
However this may be, Buthred, finding that he could not have Alfred's aid, and that he could not protect his kingdom by any force which he could himself bring into the field, tried negotiations too, and he succeeded in buying off the Danes with money.