On August 27, 1916, after Romania declared war on Austria-
Hungary, formally entered World War I, Romanian troops
cross the border of the Austro-Hungarian Empire into the
much-contested province of Transylvania.

By the outbreak of war in Europe in 1914, Romania had
long been at odds with Austria-Hungary over the issue
of territory—specifically Transylvania, which was
ethnically Romanian but then part of Hungary.

Seeing Russia’s success against Austria on the battlefields
of the Eastern Front during the summer of 1916, Romania
hoped to make an advantageous entry into the war in order
to realize long-held dreams of territorial expansion and
national unity.