An Irish monk suggested to the people around the monastery that they might pray a series of 150 Our
Fathers in place of the 150
Psalms. At first, pebbles were carried in a pouch to count the 150 Our Fathers; later ropes
with 150 or 50 (1/3 of 150)
knots were used. Eventually string with 50 pieces of wood was used.
Next the Angelic Salutation (Lk 1:28) was added. St.
Damian (d. 1072) was the first to mention this form of prayer. Soon the
Angelic Salutation replaced
the 50 Our Fathers.