'Konstantin' was the German occupation of those parts of Greece and the Balkans garrisoned by Italian forces up to the time of the Italian/Allied armistice of 8/9 September (15 September/October 1943).

Originally designated 'Prinz Eugen' (ii), the undertaking was the Balkan counterpart to 'Achse' (ii), and involved the German seizure of mainland Greece (except the area of Athens and its environs already held by them) to the south of the line extending to the south-east between Florina and the coast, the Ionian, Cyclades and Dodecanese island groups, and the eastern one-fifth of Crete.