In 1905 Philipp Lenard, the Hungarian-German physicist and winner of the Nobel Prize for Physics for his research on cathode rays and the discovery of many of their properties, visited Pressburg., In the same year, Ján Bahýľ, a Slovak inventor, flew his petrol-engine helicopter in Pressburg, reaching a height of 4 metres for more than 1500 m. As the Habsburg Empire disintegrated, the new state of Czechoslovakia was declared on 28 October 1918 in Prague. The leaders of Pressburg (where the majority of the population was German, the second biggest group was Hungarian) wanted to prevent Pozsony from becoming part of Czechoslovakia and declared the town a free town, renaming it "Wilsonovo mesto" (Wilson City) after the then President of the US, Woodrow Wilson. However, the city became part of Czechoslovakia after it was taken by the Czechoslovak Legions on 1 January 1919 (though only the left river bank; the right river bank, did not belong to Pressburg yet, was occupied only on 14 August while Budapest was occupied by the Romanian army). It was chosen as the seat of the Slovakian political organs over Martin and Nitra. The (Hungarian) Elisabeth University was originally based here, before becoming the Slovak Comenius University after the Czechoslovakian state requisitioned it on 6 January. The entire teaching staff were arrested on 28 January, because they rejected the invitation from the new Czechoslovakian government's unification celebrations. The government moved to the city on 4–5 February. On 12 February, the German and Hungarian population, who made out more 80% of the city, demonstrated against the Czechoslovak occupation in Vásár square (now SNP Square). The Czechoslovak troops opened fire, shooting at the demonstrators, leaving 9 people dead and 23 wounded. On 27 March, the town's official new name became "Bratislava" – instead of "Prešporok" (Slovak) / "Pressburg" (German) / "Pozsony" (Hungarian).