Murad I ( 1362-1389), who pursued territorial expansion even more vigor-
ously than his father Orkhan, and was an outstanding strategist, had de-
cided to bypass Constantinople for the time being. The main arm of the
Ottoman army was still the Turkish cavalry,and it made little military sense
to commit it to the storming of the walled and heavily defended city. In-
stead, he made his primary initial objective Adrianople (Edirne), the
strongest point between Constantinople and the Danube, which com-
manded the Maritsa river gap between the Balkan and Rhodope Moun-
tains.

From Adrianople, which was taken in 1361, Murad launched a three-
pronged offensive through the region. One army marched across the west-
ern Balkan passes toward Serres in Serbia and the road leading from the im-
portant port of Salonika to Belgrade. In the center, another army headed
north for Philippolis, which gave Murad control of the entire Maritsa val-
ley--the source of much of Constantinople's grain and rice supply--which
was occupied in 1363, and Sofia, which commanded the watershed be-
tween the valleys of the Nisava and the Maritsa Rivers. This forced John Pa-
laeologus to reach an accommodation with Murad in 1363 that committed
the Byzantine ruler to refrain from hatching any plots with the Balkan rul-
ers, in exchange for an Ottoman commitment not to attack Constantinople
and to allow food to reach the city. Control of the Maritsa valley also en-
abled Murad to prevent the Greeks who were resisting his advance along
the Aegean coast from linking up with the Bulgarians. At the same time, an-
other Ottoman detachment under Murad's personal command seized con-
trol of the Thracian Black Sea coast that had come under the rule of the
Bulgarian prince John Alexander ( 1355-1365) after the death of Stephen

-143-