The Psalter of John Alexander (1331–1371), a copy dating from 1337 (Sofia, BAS 2) is both the only genuine “aristocratic” psalter in Bulgarian mediaeval art and the only royal codex kept in Bulgarian libraries. Even if modestly illuminated, with one miniature at Ps. 77, some of its features are rather peculiar. In this paper they are analysed in the light of certain Byzantine concepts, like that of the “mid-Psalm” in the two-fold composition of the Book of Psalms, the imperial ideology and the encomiastic genre. The author offers an explanation of the unique arrangement of the text-pictorial units in the book as a result of sophisticated references between the theological concepts in the image of the Ancient of Days, the comments on the Creed and Lord’s Prayer on the folios preceding the image, and the religious and political situation around the enthronement of Bulgarian king.