When we say “he was a mathematician”, we usually mean someone who has contributed to mathematics as a scientific discipline. In this sense, R'atz was not a mathematician, so he is less well known in the Slovak and Czech mathematical communities. However, he was undoubtedly one of the best high school mathematics professors, who taught at perhaps the best high school, so during his 35year career he taught many brilliant students as well many excellent Hungarian mathematics teachers. They passed on this quality in Slovakia in the interwar and postwar period. Let us remember this teacher on the occasion of the 90th anniversary of his death.