Through the Markets and Bazaars - Strolling Through Istanbul: The Classic Guide to the City - page 165

RÜSTEM PAŞA MEDRESESİ
On leaving the hamam a somewhat complicated detour leads to an
interesting monument. We take Sultan Oda Sokağı, the street which
leads of to the right from Mahmut Paşa Yokuşu directly opposite the
hamam, and follow it for about 200 metres to its end; then we turn
left and then left again at the second turning. This brings us to the
medrese of Rüstem Paşa, designed by Sinan and erected, according
to an inscription, in 1550. It has a unique plan for a medrese. The
courtyard is octagonal with a columned portico of 24 domes and a
şadırvan in the centre. Behind this the cells are also arranged in an
octagonal plan, but the building is made into a square on the exterior
by filling in the corners with auxiliary rooms - baths and lavatories.
One side of the octagon is occupied by the lecture hall, a large domed
room which projects from the square on the outside like a great apse.
This fine and unique medrese has been beautifully restored.
BYZANTINE SUBSTRUCTURE ON
CEMAL NADIR SOKAĞI
From here we can extend our detour to another interesting monument
nearby. (This is part of the charm and trouble of strolling through
Istanbul: one is continually being diverted by the prospect of another
fascinating antiquity around the next corner.) Leaving the medrese,
we retrace our way for a few steps and take the first turning on the
left. This almost immediately brings us to a step street, Hakkı Tarık
Us Sokağı. At the bottom of the steps we turn left on Cemal Nadir
Sokağı and immediately to our left we see a massive retaining wall
with two iron doors and barred windows. (The doors are locked,
but can usually find a local who has the key.) This is perhaps the
most astonishing Byzantine substructure in the city, consisting of a
congeries of rooms and passages, 12 in all, every size and shape. There
is a great central hall, 16 by 10.5 metres in plan and about six metres
high, whose roof is supported by two rows of six columns, with simple
but massive bases and capitals. From this there opens another great
room, 13 by 6.7 metres, that ends in a wide apse. A series of smaller
chambers, one of them oval in shape, opens from each of these large
rooms and from the passages that lead of in all directions. The whole