The king was, to the followers of great barons, a person of but small consequence in comparison with their lord; and they would draw their swords, at the latter's order, as willingly against a king as against a foreign foe.

That it was their duty to do so was so fully recognized that, in the troubles between the king and his nobles, while the latter were, if defeated, executed for treason, their vassals were permitted to return home unmolested; and it was not until the battle of Barnet that Edward, enraged at the humiliation that he had suffered, when he had been obliged to fly to France, gave orders that no quarter was to be shown to Warwick's vassals and retainers.
Northumberland and Hotspur were still smarting under this treatment of Mortimer when, eight days after the battle, the messenger they had despatched to the king, in Wales, with the report of their great victory, and the capture of Douglas and other important nobles, returned with an order from the king that these prisoners were not to be ransomed.
This order was received with passionate indignation by the earl and Hotspur.

Although not altogether contrary to the usages of the age, since similar orders had, more than once been, issued by Edward the Third; the ransom of prisoners taken in battle was regarded as one of the most important sources of revenue, and as the means of defraying the expenses that nobles and knights were put to in aiding, with their vassals, the king in his wars.

Occasionally, however, in the case of prisoners of importance, monarchs deemed it necessary, for political reasons, to forbid the ransom of prisoners.
The Scottish nobles were as indignant as the Percys.

They had regarded it as a matter of course that they would be shortly liberated.