No More Learning

Through the thick night I hear the trumpet blow:
They summon me their King to lead mine hosts
Far down to that great battle in the west,
Where I must strike against the man they call
My sister's son--no kin of mine, who leagues
With Lords of the White Horse, heathen, and knights,
Traitors--and strike him dead, and meet myself
Death, or I know not what           doom.