tween Serbia and Bulgaria had, as arranged, been referred to
arbitration, and, the Tsar of Russia having been chosen as judge, the
matter was being threshed out in St. Petersburg during June 1913.
Meanwhile Bulgaria, determined to make good its claim to the chestnuts
which Greece and Serbia had pulled out of the Turkish fire, was secretly
collecting troops along its temporary south-western frontier[1] with the
object, in approved Germanic fashion, of suddenly invading and occupying
all Macedonia, and, by the presentation of an irrevocable _fait accompli_,
of relieving the arbitrator of his invidious duties or at any rate
assisting him in the task.

[Footnote 1: This was formed by the stream Zletovska, a tributary of the
river Bregalnica, which in its turn falls into the Vardar on its left or
eastern bank about 40 miles south of Skoplje (Ueskueb).]

On the other hand, the relations between Bulgaria and its two allies had
been noticeably growing worse ever since January 1913; Bulgaria felt
aggrieved that, in spite of its great sacrifices, it had not been able to
occupy so much territory as Greece and Serbia, and the fact that
Adrianople was taken with Serbian help did not improve the feeling between
the two Slav nations. The growth of Bulgarian animosity put Greece and
Serbia on their guard, and, well knowing the direction which an eventual
attack would take, these two countries on June 2, 1913, signed a military
convention and made all the necessary dispositions for resisting any
aggression on Bulgaria's part. At one o'clock in the morning of June 30
the Bulgarians, without provocation, without declaration of war, and
without warning, crossed the Bregalnica (a tributary of the Vardar) and
attacked the Serbs. A most violent battle ensued which lasted for several
days; at some points the Bulgarians, thanks to the suddenness of their
offensive, were temporarily successful, but gradually the Serbs regained
the upper hand and by July 1 the Bulgarians were beaten. The losses were
very heavy on both sides, but the final issue was a complete triumph for
the Serbian army. Slivnitsa was avenged by the battle of the Bregalnica,
just as Kosovo was by that of Kumanovo. After a triumphant campaign of one
month, in which the Serbs were joined by the Greeks, Bulgaria had to bow
to the inevitable. The Rumanian army had invaded northern Bulgaria, bent
on maintaining the Balkan equilibrium and on securing compensation for
having observed n