The Preface, "Concerning the Service of the Church," states that "the ancient Fathers have divided the Psalms into seven portions, whereof every one was called a Nocturn," and that "the same was . . . ordained . . . of a good purpose and for a great advancement of godliness"; but "of late time a few of them have been daily said and the rest utterly omitted." A writer of the ninth century says that S. Jerome, at the bidding of the Pope on the request of Theodosius, arranged the Psalms for the Services of day and night in order to avoid the confusion arising from variety of uses[2]. S. Ambrose was a contemporary of S. Jerome but died more than 20 years before him. There are considerable differences between the plan which S. Ambrose gave to his diocese of Milan, and the plan which we may believe was generally given at the same time to the Churches of the rest of Western Europe. But they are similar in many respects. In both, a division was made between the first 109 psalms,--which were mainly allotted to the night services, i.e. to those which were afterwards called Mattins,--and the rest which were mainly allotted to the Evening Service (Vespers). We suppose that the division, mentioned in the {43} Preface, "into seven portions" refers to those 109 Psalms. Of these 109, 18 were used at other Services, leaving 91 for Mattins, viz. 19 on Sunday and 12 each for the week days. The Ambrosian arrangement of them was for a fortnight. The Greek Church divides the whole Book into 20 portions and takes them, two portions at Mattins and one at Vespers, beginning on Saturday night, omitting Sunday Vespers, and taking, on Friday, the 19th, 20th and 18th portions. Thus we see that a weekly singing of the Book of Psalms is derived from a very ancient time, when the division of the Eastern and Western Churches of Europe had not occurred. The Sarum order, which we suppose was that which is referred to in the Preface as having been "corrupted" by omissions, had the 109 Psalms allotted to Mattins, as above described. For Vespers, there were five each day from cx.-cxlvii., omitting the 118th and 119th, 134th, 143rd and, as explained below[3], reckoning the 147th as two. All these were taken in order as they stand in the Bible. Those which were left out were allotted to other Services, as, for instance, iv. to Compline, lxiii. to Lauds, &c., &c. Psalm cxix. was to be said through every day, 32 verses at Prime, and 48 verses each, at Terce, Sext and None. {44} Lauds was the great Praise Service of the day, and had a very beautiful arrangement of its Psalms which always ended with one of the O.T. hymns followed by Psalms cxlviii.-cl. The O.T. hymns on the seven days of the week were _Benedicite_: Isaiah xii.: Isaiah xxxviii. 10-20: 1 Sam. ii. 1-10: Exodus xv. 1-19: Hab. iii.: Deut. xxxii. 1-43. The beauty of many of these arrangements is undeniable: but they were rather intricate; and in practice they broke down.