The Noemvriana (Νοεμβριανά, "November Events") of , or the Greek Vespers (after the Sicilian Vespers), was a political dispute which led to an armed confrontation in Athens between the royalist government of Greece and the forces of the Allies over the issue of Greece's neutrality during World War I.
Friction existed between the two sides from the beginning of World War I. The unconditional surrender of the border fortress of Roupel in May 1916 to the Central Powers' forces, mainly composed of Bulgarian troops, was the first event that led to the Noemvriana. The Allies feared the possibility of a secret pact between the Greek royalist government and the Central Powers. Such an alliance would endanger the Allied army in Macedonia bivouacking around Thessaloniki since the end of 1915. Intensive diplomatic negotiations between King Constantine I and Allied diplomats took place throughout the summer. The king wanted Greece to maintain her neutrality, a positio