The Czech Christmas Mass called "Hey Master, get up, quickly!" by Jakub Jan Ryba (1765-1815) became one of the most important works of one of the best educated Czech schoolmasters and musicians of his time who found his destiny in the school employment in the small town of Rozmital pod Tremsinem. There, Ryba increasingly engaged in diverse activities in the fields of enlightenment, didactics, literature and music. Among the works he left as a composer, we find a number of masses set to Latin texts, but only one to a Czech adaptation of the story of Christ's birth in Bethlehem, following the example of popular nativity plays. Form the first performance at Christmas in 1796, Ryba's Czech Mass has gradually become a symbol of Czech Christmas holidays and is frequently performed until today.