First Balkan War: The Battle of Lemnos begins; Greek admiral Pavlos Kountouriotis forces the Turkish fleet to retreat to its base within the Dardanelles, from which it did not venture for the rest of the war.

The First Balkan War lasted from October 1912 to May 1913 and involved actions of the Balkan League against the Ottoman Empire. The Balkan states' combined armies overcame the initially numerically inferior and strategically disadvantaged Ottoman armies, achieving rapid success.

The Naval Battle of Lemnos, fought on 18 January [O.S. 5 January] 1913, was a naval battle during the First Balkan War, in which the Greeks defeated the second and last attempt of the Ottoman Empire to break the Greek naval blockade of the Dardanelles and reclaim supremacy over the Aegean Sea. This, the final naval battle of the First Balkan War, forced the Ottoman Navy to retreat to its base within the Dardanelles, from which it did not venture for the rest of the war, thus ensuring the dominion of the Aegean Sea and the Aegean islands by Greece.

Pavlos Kountouriotis was a Greek admiral who served during the Balkan Wars, was regent of Greece, and the first president of the Second Hellenic Republic. In total he served four times as head of the Greek state, the most times in the history of the seat.

The Dardanelles, also known as the Strait of Gallipoli and in classical antiquity as the Hellespont, is a narrow, natural strait and internationally significant waterway in northwestern Turkey that forms part of the continental boundary between Asia and Europe and separates Asian Turkey from European Turkey. Together with the Bosporus, the Dardanelles forms the Turkish Straits.