ndeed to many one of the legacies of the Founder of
Christianity. The familiar petition in the Lord's Prayer: _thy kingdom
come, thy will be done on earth as it is in heaven_ sounded, in the ears
of Dante and Thomas Aquinas and innumerable theologians and canonists,
as a prayer and a pledge for the ultimate political unity of mankind on
the basis of Christian Law. Such a belief was indeed the bedrock of
mediaeval political thought. To devout Christians, brought up in the
oecumenical traditions of the Roman Empire,

'every ordering of a human community must appear as a
component part of that ordering of the world which exists
because God exists, and every earthly group must appear as
an organic member of that _Civitas Dei_, that God-State,
which comprehends the heavens and the earth.[1] ... Thus the
Theory of Human Society must accept the divinely created
organization of the Universe as a prototype of the first
principles which govern the construction of human
communities.... Therefore, in all centuries of the Middle
Age, Christendom, which in destiny is identical with
Mankind, is set before us as a single, universal Community,
founded and governed by God Himself. Mankind is one
"mystical body"; it is one single and internally connected
"people" or "folk"; it is an all-embracing corporation,
which constitutes that Universal Realm, spiritual and
temporal, which may be called the Universal Church, or, with
equal propriety, the Commonwealth of the Human Race.
Therefore, that it may attain its one purpose, it needs One
Law and One Government.'[64]

But the mediaeval ideal, like the Greek, broke down in practice. 'Where
the Middle Ages failed', says the Master of Balliol, continuing a
passage already quoted, 'was in attempting ... to make politics the
handmaid of religion, to give the Church the organization and form of a
political State, that is, to turn religion from an indwelling spirit
into an ecclesiastical machinery.' In other words, the mediaeval attempt
broke down through neglecting the special conditions and problems of the
political department of life, through declining, as it were, to
specialize. While men were discussing the Theory of the Two Swords,
whether the Emperor derived his power directly from God or indirectly
through the Pope, or whether the sword should be used at all, the actual
work of government in lay