Compromise of 1867, the factor of spontaneous assimilation should be given due weight in any analysis relating to the demographic tendencies of the Kingdom of Hungary in the 19th century. The other key factor in mass ethnic changes is that between 1880 and 1910 about 3 million people from Austria-Hungary migrated to the United States alone. More than half of them were from Hungary (at least 1.5 million or about 10% of the total population) alone. Besides the 1.5 million that migrated to the US (two thirds of them or about a million were ethnically non-Hungarians) mainly Romanians and Serbs had migrated to their newly established mother states in large numbers, like the Principality of Serbia or the Kingdom of Romania, who proclaimed their independence in 1878. Amongst them were such noted people as the early aviator Aurel Vlaicu (represented on the 50 Romanian lei banknote), writer Liviu Rebreanu (first illegally in 1909, then legally in 1911), and Ion Ivanovici. Many also migrated to Western Europe and other parts of the Americas. Allegation of violent oppression Many Slovak intellectuals and activists (such as national activist Janko Kráľ) were imprisoned or even sentenced to death for high treason during the Hungarian Revolution of 1848. One of the incidents that shocked European public opinion was the Černová (Csernova) massacre in which 15 people were killed and 52 injured in 1907. The massacre caused the Kingdom of Hungary to lose prestige in the eyes of the world when English historian R. W. Seton-Watson, Norwegian writer Bjørnstjerne Bjørnson and Russian writer Leo Tolstoy championed this cause. The case being a proof for the violence of Magyarization is disputed, partly because the sergeant who ordered the shooting and all the shooters were ethnic Slovaks and partly because of the controversial figure of Andrej Hlinka. The writers who condemned forced Magyarization in printed publications were likely to be put in jail either on charges of treason or for incitement of ethnic hatred. Education Schools funded by churches and communes had the right to provide education in minority languages. These church-funded schools, however, were mostly founded before 1867, that is, in different socio-political circumstances. In practice, the majority of students in commune-funded schools who were native speakers of minority languages were instructed exclusively in Hungarian. Beginning with the 1879 Primary Education Act and the 1883 Secondary Education Act, the Hungarian state made more efforts to reduce the