all learning, a Mystical form having the mysterious figure of the
Vesica Piscis, the true Gothic Arch, with the Equilateral Triangle
enclosed as its unit, and symbolising the Trinity in Unity. The
recognition of the import of the Trinity was paramount throughout
those early days; all important documents began with an Invocation of
the _Tres Personae_, or were garnished with symbolic illustrations
thereof; all the old MSS., already referred to, which have come down
to us from that period, invariably commence with "In the name of the
Father and of the Son and of the Holy Ghost."

It can therefore be readily understood what determined the sudden
change between 1140-1150, resulting in that wonderful accession of
beauty to architectural design which we find in the Gothic. The
incentive had to be a strong one, and of an eminently religious
character, to accomplish the radical change of throwing over so
absolutely the Norman, and commencing to build entirely on what are
called Gothic lines. A careful examination of the proportions of the
structures themselves, and the character of the decorations found in
the finest examples of buildings representing that style, at once
shows us that the incentive was the symbolism attached to the
mysterious figure called the Vesica Piscis, which appears to be not
only the principal feature upon which the whole style rests, but is
also employed, as a symbol of the Divine, wherever we have Gothic
Architecture, either in painted windows or mural decorations. Every
Cathedral has its Vesica Piscis, often of enormous dimensions.
Geometry was synonymous with Masonry, and the very _foundation_
of the Science of Geometry, as expounded by Euclid, was his
_first_ proposition. _Every single problem_ in the whole of his
books necessitates for its construction the use of this one
foundation--namely, "how to form an Equilateral Triangle," and this is
the Mystical form of "the Knowledge of the Square." This triangle,
symbolising the Logos, is therefore not only the _beginning_ of the
Science of Geometry, and therefore of Masonry, the Head of all the
Sciences, but it is by that triangle that all Geometrical forms, and
therefore forms of knowledge, are _made_, and it became the most
mysterious and secret symbol of the Logos, for is it not written by
St. John that "In the beginning was the Logos, and by it were all
things made"; so the Vesica Piscis, the cradle of the Logos, became
the great _secret_ of Masonr