Army of the Wolf. Crusader Chronicles, #1

The Sword Brothers have won a great victory and the implacable enemy of their order is dead. There is now nothing to stop the Bishop of Riga from marching north and seizing the whole of Estonia. But in the moment of triumph the seeds of future difficulties have been sown, for the bishop's German crusaders believe that the fight against the pagans has been won and thus there is no reason for them to stay in Livonia.
Faced with a lack of holy warriors to complete his task, the bishop is forced to beg the ambitious King Valdemar of Denmark for military aid, a request that will have disastrous consequences. While he is away Conrad Wolff, now a veteran brother knight of the Sword Brothers, his reputation high among pagans and crusaders alike, is sent to Ungannia whose ruler Kalju is an ally of the Sword Brothers.
There a trivial incident escalates into a full-scale war that results in a great barbarian horde sweeping into Livonia and threatening the very existence of the crusader state. Conrad is sent on a desperate mission to raise a ragtag army to delay the invaders long enough so Riga can summon crusader knights from Germany. Conrad and his companions soon find themselves battling Cumans, Russians, Lithuanians and Danes as their motley force - the Army of the Wolf - takes the field against the many enemies of Livonia.
This, the second volume of the Crusader Chronicles, continues the story of Conrad Wolff and the Baltic Crusade in the first quarter of the thirteenth century.