Yekatit 12 is a date in the Ethiopian calendar, equivalent to 19 February in the Gregorian calendar, which is commonly used to refer to the indiscriminate massacre and imprisonment of Ethiopians by elements of the Italian occupation forces following an attempted assassination of Marshal Rodolfo Graziani, Marchese di Neghelli, Viceroy of Italian East Africa, on 19 February 1937. Marshal The Marchese di Neghelli had led the Italian forces to victory over their Ethiopian opponents in the Second Italian invasion of Ethiopia and was supreme governor of Italian East Africa. This was one of the worst atrocities committed by the Italian occupation forces.
Estimates of the number of people killed in the three days that followed the attempt on the Marchese di Neghelli's life vary. Ethiopian sources afterwards estimated as many as 30,000 people were killed by the Italians, while Italian sources claimed only a few hundred were killed. Over the following week, numerous Ethiopians suspected or accused of opposing Italian rule were rounded up and executed, including members of the Black Lions, and other members of the aristocracy; most of the 125 young men whom Emperor Haile Selassie had sent abroad to receive college education, and were still resident in Ethiopia, were killed. Many more were imprisoned, even collaborators like Ras Gebre Haywot, the son of Ras Mikael of Wollo (who had been imprisoned by Emperor Haile Selassie for nine years prior to the Italian invasion), Brehane Markos, and even Ayale Gebre; the latter had helped the Italians identify the two men who made the attempt on General Graziani's life.