The original inventory also survives however (or else a 15th-century copy of it). It includes a description, slightly different in interesting ways, of the same four-volume set:
123. Item epistole et euuangelia ab adventu usque ad pascha in uno volumine quod cum aliis tribus voluminibus facit integrum missale de pulchra et grossa littera n duplici margine. incipit in 2o folio apropinquarent erosolime et in penultimo ducaveritis carnem [crossed through: quorum voluminum ...] precii x librarum
124. Item epistole et euuangelia a dominica prima post pascha in simili volumine incipit in 2o folio meus et deus meus et in penultimo pondens ihesus precii x librarum ut supra
125. Item prima pars cuiusdam missalis continens officium et collectas atque euuangelia ab adventu usque ad pascha cum communi in simili volumine cum kalendario incipit in 2o folio post kalendarium et si quis vobis et in penultimo eius tibi gracia precii x librarum
126. Item tercia pars eiusdem missalis ubi sunt collecte cum responsoriis et allelluia et offertoriis et collectis incipiens a prima dominica post pascha incipit in 2o folio post kalendarium angelus domini et in penultimo te domine suppliciter cum nota precii x librarumFirst, we may note that the verba probatoria prove beyond any doubt that the four volumes are the same ones as those described in the later inventory. We can summarise the contents of the four volumes and the numbering applied to them like this:
- Epistle and Gospel readings together in one volume
- from Advent to Easter
- from the first Sunday after Easter onwards
- Offices, collects, and Gospel readings, with the Common and a calendar
- I ("prima pars"): from Advent to Easter
- Collects with responsories, alleluyas, offertories, and collects
- III ("tercia pars"): from the first Sunday after Easter onwards
The first two volumes are not numbered as part of their 4-volume set in these descriptions (although they have inventory numbers "123" and "124" in the margin), yet they clearly were considered to be a set, because the first one is 'in one volume that, with the three other volumes, make a complete missal, in large and beautiful script, in double columns'.
The third description, as originally written, was described a "tercia pars missalis", but the scribe then crossed this through and changed it to "prima pars cuiusdam missalis":
The fourth description here corresponds to the second volume in the 18th-century inventory. In the present document it is described last, so we would expect it be be described either as the fourth volume of the whole set, or else the second volume of the two main Missal volumes, but instead it is called the "tercia pars". It is therefore highly suggestive that this is the one that most closely matches the surviving volume of the Hangest Missal.
How can we account for this confusion in the numbering of the volumes?
We are told by the 1926 Sotheby's description that the Hangest inscription was "On the blank recto of the first leaf of the calendar". This is very surprising, because in 99% of cases a calendar occupies 6 or 12 leaves (with each month occupying either a single page, or both sides of a single leaf), beginning on a recto and ending on a verso. But it is confirmed by the extant calendar leaf sold at Sotheby's in 1985 (recto: February; verso: March) and by the one at Harvard (recto: August; verso: September) that the Hangest calendar was unusual: the first page of the first leaf of the calendar would originally have been blank, with January starting on the verso.
Anyone in the 15th century opening the book at the beginning would have immediately encountered the Hangest "tercia pars" inscription, presumably on an otherwise blank page, before getting to the actual text. It seems quite likely that this is what happened to the cataloguer in December 1464. Perhaps he began to describe the third of his the volumes as the "tercia pars", but then, because he knew that the fourth volume describes itself as the "tercia pars", he changed this to "prima pars".
Added to the fact that each volume of the four-volume set discussed above is valued at very high price of 10 livres, and was kept in the treasury, the identification becomes even more compelling.
If the two descriptions reproduced and transcribed above do describe the Hangest Missal, what else can they tell us? One or two thoughts will be addressed in the next post.
 The mention of "officiu[m]" is odd. Perhaps the compiler turned a few leaves of the book and saw the abbreviation "Off." of the offertories and either misunderstood; or looked at a page like this, which has the rubric "In die offitium":