Along the Golden Horn - Strolling Through Istanbul: The Classic Guide to the City - page 310

Eratosthenes. This is perhaps the single most important work of the
greatest mathematical physicist of antiquity, and constitutes a very
great addition to our knowledge of ancient science.
Passing St. George's and continuing along Vodina Caddesi to
the next corner, we turn left and follow the walled enclosure along
a steep cobbled street leading uphill. A little way up the hill we see
another iron gate which leads to the second of the two churches
in this enclave. This is the church of the Panaghia Paramithias (St.
Mary the Consoler), which served as the Patriarchal church from
1586 till 1596, in the years just after the Patriarchate was moved
from the Pammakaristos. Notice the double eagle carved on the
marble flagstone at the entrance to the church; this is the symbol
of the imperial Palaeologan dynasty and of the Greek Orthodox
Patriarchate. This church is more commonly called Vlach Saray, or
the Palace of the Wallachians, because it was attached to the adjacent
palace of the Cantacuzenus family, who were Hospodars of Wallachia
as well as of Moldavia. Unfortunately, Vlach Saray was destroyed by a
fire in 1976, and only charred ruins remain to be seen today.
ST. MARY OF THE MONGOLS
Continuing up the hill we turn left at the corner and then take
the second right. We then see ahead a rose-red Byzantine church,
deformed in shape and with an unusually high drum. This is the
church dedicated to the Theotokos Panaghiotissa, the All-Holy
Mother of God, but it is more generally called the Mouchliotissa,
or St. Mary of the Mongols. This church was founded, or rebuilt,
in about 1282 by the Princess Maria Palaeologina, an illegitimate
daughter of the Emperor Michael VIII Palaeologus. In the year 1265
Maria was sent by her father as a bride to Hulagu, the Great Khan
of the Mongols. Hulagu died before Maria arrived at the Mongol
court, however, so she was married instead to his son and successor
Abagu. Maria lived at the Mongol court in Persia for about 15 years,
and through her influence the Khan and many of his court became
Christians. But then, in 1281, Abagu was assassinated by his brother
Ahmet and Maria was forced to return to Constantinople. After
Maria's return her father ofered her as a bride to still another Khan