idea of the Roman Empire, its theoretical justification, might be
described as the realisation of the unity of the world by the
establishment of a common order, the unification of mankind in a
single world-embracing political organism. The term "world," orbis
(terrarum), which imperial poets use freely in speaking of the
Empire, is more than a mere poetical or patriotic exaggeration; it
expresses the idea, the unrealised ideal of the Empire. There is a
stone from Halicarnassus in the British Museum, on which the idea is
formally expressed from another point of view. The inscription is of
the time of Augustus, and the Emperor is designated as "saviour of
the community of mankind." There we have the notion of the human
race apprehended as a whole, the ecumenical idea, imposing upon Rome
the task described by Virgil as regere imperio populos, and more
humanely by Pliny as the creation of a single fatherland for all the
peoples of the world. [Footnote: Pliny, Nat. Hist. iii. 6. 39.]

This idea, which in the Roman Empire and in the Middle Ages took the
form of a universal State and a universal Church, passed afterwards
into the conception of the intercohesion of peoples as contributors
to a common pool of civilisation--a principle which, when the idea
of Progress at last made its appearance in the world, was to be one
of the elements in its growth.

3.

One remarkable man, the Franciscan friar Roger Bacon, [Footnote: c.
A.D. 1210-92. Of Bacon's Opus Majus the best and only complete
edition is that of J. H. Bridges, 2 vols. 1897 (with an excellent
Introduction). The associated works, Opus Minus and Opus Tertium,
have been edited by Brewer, Fr. Rogeri Bacon Opera Inedita,