3. The Mass, which we call the Communion Service, was contained in the _Missale_, so far as the text was concerned. The Epistles and Gospels, being read at separate lecterns, would often be written in separate books, called _Epistolaria_ and _Evangeliaria_. The musical portions of the Altar Service were latterly all contained in the _Graduale_ or Grayle, so called from one of the principal elements being the _Responsorium Graduale_ or Respond to the _Lectio Epistolae_. In earlier times, these musical portions of the Missal Service were commonly contained in two separate books, the _Graduale_ and the _Troparium_. The _Graduale_, being in fact the _Antiphonarium_ of the Altar Service (as indeed it was called in the earliest times), contained all the passages of Scripture, varying according to the season and day, which served as Introits (_Antiphonae et Psalmi ad Introitum_) before the Collects, as Gradual Responds or Graduals to the Epistle, as _Alleluia_ versicles before the Gospel, as _Offertoria_ at the time of the first oblation, and as _Communiones_ at the time of the reception of the consecrated elements. The _Troparium_ contained the _Tropi_, or preliminary tags to the Introits; the Kyries; the _Gloria in excelsis_; the Sequences or _Prosae ad Sequentiam_ before the Gospel; the _Credo in unum_; the _Sanctus_ and _Benedictus_; and the _Agnus Dei_; all, in early times, liable to have insertions or _farsuræ_ of their own, according to the season or day, which, however, were almost wholly swept away (except those of the _Kyrie_) by the beginning of the thirteenth century. Even in Lyndewode's time (A.D. 1433), the _Troparium_ was explained to be a book containing merely the Sequences before the Gospel at Mass, so completely had the other elements then disappeared or become incorporated in the _Graduale_. This definition of the _Troparium_ is the more necessary, because so many _old_ church inventories yet remain, which contain books, even at the time of writing the inventory long since disused, so that the lists would be unintelligible without some such explanation. _Occasional Services._ 4. The Occasional Services, so far as they concerned a priest, were of course more numerous in old days than now, and included the ceremonies for _Candle_mas, _Ash_ Wednesday, _Palm_ Sunday, &c., besides what were formerly known as the Sacramental Services. The book which contained these was in England called the _Manuale_, while on the Continent the name _Rituale_ is more common. No church could well be without one of these. The purely episcopal offices were contained in the _Liber pontificalis_ or Pontifical, for which an ordinary church would have no need. _The Ordinale._