This brief contribution aims at exposing in a succint way the procedures used by scribes from Southern Italy to distinguish the different constituent parts of the Byzantine euchologion: prayers, rubrics, diaconal interventions. The analysis starts from the most ancient manuscript, the Barberini Euchologion (8th century), the only manuscript we preserve written in capital letters. Hereafter we describe the changes introduced by the advent of the minuscule handwriting in the book layout from the 10th-12th centuries.