More than a thousand years ago, the ruler of a beleaguered kingdom saw a vision of the Virgin Mary that moved him to rally his chiefs and make a last stand. Alfred the Great freed his realm from Danish invaders in the year 878 with an against-all-odds triumph at the Battle of Ethandune. In this ballad, G. K. Chesterton equates Alfred's struggles with Christianity's fight against nihilism and heathenism--a battle that continues to this day. One of...