Fernand Cabrol says that Prime originally used only a repetition of the Lauds Psalms 1, 57 (58), and 89 (90), but the monasteries that gradually adopted the new office in changed its constitution as they liked. In spite of the many variations, one characteristic feature is the recitation of the Athanasian Creed. Saint Benedict assigns to Prime on Sundays four groups of eight verses of Ps. 118 (119), and on week-days three psalms, beginning with the first and continuing to Ps. 19 (20), taking three psalms each day (Pss. 9 (10) and 17 (18) being divided into two). This makes Prime like the other Little Hours of the day, which it resembles these in accompanying the psalms with a hymn, an antiphon, capitulum, versicle, and prayer. The Roman Breviary as decreed by Pope Pius V in 1568 in line with the decrees of the Council of Trent, assigns to Prime on Sunday of Pss. 53 (54), 107 (108) and the first four groups of eight verses of Ps. 118 (119); on each of the weekdays it assigns the same psalms as on Sunday except that it replaces Psalm 107 (108) with Psalm 23 (24). Each day therefore had in Prime two full psalms and the same two portions of Psalm 118 (119). The late 1911 reform of the Roman Breviary by Pope Pius X changed the psalmody radically, dividing several psalms into shorter portions. To Prime it assigned each day three psalms or portions of psalms, each day different.