Christendom is the part of the world inhabited by Christians, understood as a polity ordered toward Christ though recognition of the authority of the Church. The ordering of course has never been perfect, but Christ was nonetheless once understood as the principle of unity and the highest possible authority. As such, Christendom endured until the Enlightenment. Even into the Twentieth Century in many parts of Europe peasants habitually referred to themselves as “Christians” rather than by nationality or ethnicity, and into the middle of that century the Christian countries could be referred to in public as Christian countries.
With the decline of Church authority and unity Christendom, or at least Latin Christendom, became first “Europe” and then “The West.” Our political world is thus the remains of Latin Christendom, now in disorder because it has lost touch with the central realities that once ordered it.
Religion—the accepted understanding of the nature of man and the world—is the fundamental principle of every political order. Current liberal understandings seem unable to maintain social order in the long run. The restoration of Christendom is therefore a necessity if our civilization is to continue in anything like its historic form.