Ján Kollár (1793–1852), writer, poet, Slavist, and archaeologist, was a Slovak patriot who championed the Slav struggle against foreign oppression. Ludovít Stúr (1815–56) is the founder of the Slovak literary language and modern Slovak literature. Founder of scientific Slavic studies was Pavel Josef Safacrík (1795–1861), whose Slavonic Antiquities had great scholarly influence. Andrej Hlinka (1864–1938) led the Slovak Catholic autonomist movement. The greatest Slovak poet, Pavel Hviezdoslav (1849–1921), translated foreign poetry, refined the language, and contributed to Slovak awakening. The Robin Hood of the Slovaks, Juraj Jánošík (1688–1713), fought the Hungarians. Milan Rastislav Stefánik (1880–1919), military leader, astronomer, and ally of Tomáš Masaryk, represented the Slovaks in their struggle for liberty. Alexander Dubcek (1921-92) was first secretary of the Czechoslovak Communist Party (1968-69). His attempt to increase civil liberties led to the invasion of Czechoslovakia by the Warsaw Pact in 1968. In 1989 he was elected the Federal Assembly's first speaker.