This article contains a bilingual, Latin-Polish, edition of a letter written by Erasmus to John Sixtin (Ioannes Sixtinus), a Frisian student he met in England. In it Erasmus describes a dinner party at Oxford to which he was invited as an acclaimed poet. In the presence of John Colet, leader of English humanists, table talk turned into learned conversation. Erasmus’s contribution to the debate was an improvised fable (fabula) about Cain who, in order to become farmer, persuades the angel guarding Paradise to bring him some seeds from the Garden of Eden. His speech, a showpiece of rhetorical artfulness disguising a string of lies and spurious argument, is so effective that the angel decides to steal the seeds and thus betray God’s trust. Seen in the context of contemporary surge of interest in the art of rhetoric, Erasmus’ apocryphal spoof is an eloquent demonstration of the heuristic value of mythopoeia and the irresistible power of rhetoric.