The Greco-Turkish War of 1897, also called the Thirty Days’ War and known in Greece as the Black ’97 (Greek: Μαύρο ’97, Mauro ’97) or the Unfortunate War (Ατυχής πόλεμος, Atychis polemos) (Turkish: 1897 Osmanlı-Yunan Savaşı or 1897 Türk-Yunan Savaşı), was a war fought between the Kingdom of Greece and the Ottoman Empire. Its immediate cause was the question over the status of the Ottoman province of Crete, whose Greek majority long desired union with Greece. Despite the Ottoman victory at the field, an autonomous Cretan State under Ottoman suzerainty was established the following year (as a result of the intervention of the Great Powers after the war), with Prince George of Greece and Denmark as its first High Commissioner.
This was the first war effort in which the military and political personnel of Greece were put to test since the Greek War of Independence in 1821. For the Ottoman Empire, this was also the first war effort in which the reorganized military personnel were put to test. The Ottoman army was under the guidance of a German military mission led by Colmar Freiherr von der Goltz, who had reorganized it after the defeat in the Russo-Turkish War (1877–1878).
The conflict proved Greece was wholly unprepared for war. Plans, fortifications and weapons were non-existent, the mass of the officer corps was unsuited to its tasks, and training was inadequate. As a result, the numerically superior, better organized, equipped and led Ottoman forces pushed the Greek forces south out of Thessaly.