f its conversion into a museum of arms, thus affording
exceptional facilities for the erection of scaffolding and the removal
of plaster and other obstructions. Mr. George gave nearly five months to
the study of the church, and the results of his careful investigations
will appear in a monograph to be published by the Byzantine Research and
Publication Fund. But with great courtesy, in view of the fact that I
was engaged on the present work, and also because I waived my own
application for leave to study S. Irene in favour of the application
made by the Byzantine Fund, I have been allowed to anticipate that
monograph by making use of some of the results of Mr. George's
investigations. For this permission I am very grateful, as it will add
much to the value of this volume. I visited the church frequently while
Mr. George was at work upon it, and my account of its architectural
features is based entirely upon the information he then kindly supplied,
and upon the notes he has communicated to me since his return to
England.

[Illustration: PLATE XIX.
(1) S. IRENE. VAULTING AT THE NORTH-WEST CORNER OF THE ATRIUM.
(2) S. IRENE. THE NORTHERN ARCH OF THE MAIN DOME, SEEN FROM
THE SOUTH GALLERY.
_To face page 92._]

The architectural feature which gives to this building a peculiar
interest, in the study of the development of planning and construction,
is the more complete fusion of the basilican type of plan with a domical
system of roofing which it presents than is found in any other example
of a similar combination.

On the west, where the ground retains its original level, stands the old
atrium, though much modified by Turkish repairs and alterations. It had
covered arcades on the north, south, and west sides, but only the outer
walls of the northern and southern arcades, with some portions of their
inner walls, and three complete vaulted bays at the northern end of the
western arcade, are Byzantine. The walls, vaults, and piers in other
parts of the arcades are Turkish. There is no trace of the west door
which, under ordinary circumstances, would form the main entrance to the
atrium, but a Byzantine doorway, now built up, is found close to the
narthex, in the outer wall of the south arcade. The area of the atrium
has been, moreover, greatly reduced by the erection, on its four sides,
of an inner range of Turkish vaulting.

Five doors led from the atrium to the narthex, but only the central and
the northernmost