Advance & retreat - HARRY TURTLEDOVE

When Avram became King of Detina, he announced his intention to liberate the blond serfs from their ties to the land. This noble assertion immediately plunged the kingdom into a civil war that would prove long and bloody, and set brother against brother. The northern provinces, dependent on the labour of their serfs, seceded, choosing Avram's cousin, Grand Duke Geoffrey, as their king. To save the kingdom, Avram sent armies clad in grey against the north, battling Geoffrey's army, arrayed in blue. Though King Avram held more land and wealth than Geoffrey, Geoffrey's men were better soldiers and the north had better and more powerful wizards. Still, as the war raged on, the tide turned against the north. Even so, the war is far from over. Earlier, the north had held an almost impregnable position - but was overrun when an overconfident sorcerer's spell went awry. Use of sorcery was often unpredictable, and in the more mundane aspects of the war, battle plans could also go awry. The south seemed to be winning, but the outcome was far from certain...