In this very tense atmosphere it was decided that a plebiscite would be held in the area asking people which country this territory should join. Plebiscite commissioners arrived there at the end of January 1920, and after analysing the situation declared a state of emergency in the territory on 19 May 1920. The situation in the area remained very tense, with mutual intimidation, acts of terror, beatings and even killings. A plebiscite could not be held in this atmosphere. On 10 July both sides renounced the idea of a plebiscite and entrusted the Conference of Ambassadors with the decision. Eventually, on 28 July 1920, by a decision of the Spa Conference, Czechoslovakia received 58.1% of the area of Cieszyn Silesia, containing 67.9% of the population. It was this territory that became known from the Polish standpoint as "Zaolzie" – the Olza River marked the boundary between the Polish and Czechoslovak parts of the territory.