Some medieval theologians considered the 150 Psalms to
be veiled mysteries about the life, death and resurrection of
Jesus. They began to compose "Psalters of Our Lord and
Savior Jesus Christ" - 150 praises in honor of Jesus. Soon
psalters devoted to 150 praises of Mary were composed.
When a psalter of 150 praises in Mary's honor numbered
50 instead of 150, it was called a
, or bouquet.