Stefan’s mentor Marian Koller used to be the very-best astronomer from Carniola besides Augustin Hallerstein. Today, his work connected with Dalton minimum is again in limelight as the alternative explanation of disputed global warming phenomena. Koller decisively supported Josef Stefan, a Slovene from Klagenfurt, who won his blitzkrieg pedagogical path from a high school professor to the leading scholar in the Habsburg Monarchy. His greatest helper was his fellow Slovenian Marian Koller, a Benedictine erudite from Bohinj as a leading counsellor at the Ministry of Education. The successful cooperation of both leading Slovenian experts promoted the Habsburgian sciences worldwide. Koller’s international connections and pedagogical-scientific ideas enabled early success of young Stefan. In his turn, Stefan made his atomistic kinetic theories mandatory in Habsburgian monarchy except for Ernst Mach’s Prague which traditionally opposed Viennese ideas already during the prevailing influences of Jesuit Rudjer Boskovic’s sciences a century earlier.