János Bolyai (1802 - 1860) Hungarian mathematician, son of Farkas Bolyai. In the 1820s, János studied in Vienna, where he developed a keen interest in Euclid’s parallel postulate
, to the dismay of his father. By 1832, however, Farkas acknowledged his son’s innovations in the field and published them as an appendix to his textbook. He accomplished a lot in the advancement of the study of non-Euclidean geometry. A 135 km crater on the moon is named after János Bolyai.