Mangan's first verses were published in 1818. From 1820 he adopted the middle name Clarence. In 1830 he began producing translations – generally free interpretations rather than strict transliterations – from German, a language he had taught himself. Of interest are his translations of Goethe. From 1834 his contributions began appearing in the "Dublin University Magazine". In 1840 he began producing translations from Turkish, Persian, Arabic, and Irish. He was also known for literary hoaxes; some of his "translations" are in fact works of his own, like "Twenty Golden Years Ago", attributed to a certain Selber.