Rumno was a large village with more than 2,500 inhabitants during the Second World War, Poles made up about 30% of the population.

On the night of 2/3.06.1944 members of the Ukrainian Insurgent Army attacked Polish homesteads. At that time 28 people were killed. The next day after the attack the bodies were found and hurriedly buried in the Rumno cemetery in a mass grave in the presence of the parish priest Bolesław Bydoń. After the burial, the Poles left the village and took refuge in Chlopy, where there was Polish self-defence.

On 17.09.1944, on the 50th anniversary of the murder of the Poles, after obtaining all the necessary permits, the former inhabitants of Rumno, headed by Father Tadeusz Pater, unveiled a commemorative cross on the grave of the Poles murdered in 1944. This new commemoration was dedicated to 40 people - victims murdered during the aforementioned attack and those who died later (until the end of October 1944). The inscription on the arms of the cross reads: "He loved us to the end" and the number 40. At the foot of the cross is a plaque with the inscription in Polish and Ukrainian: "To the memory of the Poles, inhabitants of Rumno, who died a sacrificial death in the summer of 1944 / On the fiftieth anniversary of these events from the remembering compatriots, September 1994".