132 ALEXANDER'S EASTERN EXPEDITION. [CHAP.
disappointment at this event was extreme, because it involved the
prolongation of the war and greatly increased his difficulties;
at the same time he had no choice but to wait at
pyius in Hecatompylus, the chief city of Parthia, until he
Parthia. was jojne(j j^ the rernainder Of the army. Mean-
while Bessus had escaped over the mountains into Bactria, and
into that country it was necessary that Alexander should pursue
him; but with the provident vigilance which he displayed in all
his campaigns, that commander determined first to secure the
districts which he would have in his rear, when he advanced in
that direction. Owing to this, and to the treachery of the
Persians who submitted to him, he spent the remainder of this
year in a desultory warfare, which led him by a devious route
into regions about which at all times but little information has
been obtainable.
His first expedition was through the mountains at the foot of
which Hecatompylus was situated, with the view
of subjugating the Hyrcani and other races who
occupied the country to the southward of the
Caspian Sea. The people from whom he experienced the most
vigorous resistance were the Mardi, a tribe who inhabited a
region difficult of access on account of its ruggedness and in-
tricacy. The description which Curtius has given of this as a
mountain district clothed with dense forests1 closely corresponds
with what we know at the present day of the ground which
intervenes between Mt Elburz and the Caspian.
^ T*e Caspian It ^ ^ ^ time that the Greeks obtained a
view of that sea, and, if we may believe Plutarch,
Alexander's first impression on seeing this expanse of water was
that it was an outflow from the Palus Maeotis*. The ignorance
of the geography of these parts which this betrays may appear
strange, but is hardly more so than other mistakes which will
presently be noticed. Returning from this expedition, Alex-
ander now marched eastwards through the north of Parthia, and
1 Curt., Hist. Alex., 6. 5. 13.
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