This contribution brings a critical edition of a short treatise by Jakoubek of Mies and ranks the work among the eldest utraquist works – it originated in August 1414 most probably. Articulus brings evidence that the most important auctoritas of the time when the idea of the cup originated was the vers of Paul´s 1. epistle to the Corinthians Probet autem se ipsum homo and it is a relevant testimony of Matěj´s of Janov influence on the origin of utraquism.