A Dictionary of Music and Musicians/Inscription
INSCRIPTION (Lat. Inscriptio, Ital. Motto). A Motto, or Sign, or combination of both, placed at the beginning of a Canon, to indicate, more or less clearly, the manner of its Resolution.
During the latter half of the 15th century, the founders of the Flemish School—by whom the more abstruse forms of Imitation were assiduously cultivated—seem chiefly to have aimed at rendering the solution of their Enimme, or Ænigmatical Canons, impossible. Some of their most extravagant conceits are presented in the shape of Crosses, Circles, Squares, Triangles, Rainbows, Chess-boards, Sun-dials, and other equally fantastic designs, without the addition of any clue whatever to their hidden meanings. (See examples in Hawkins, Hist. chap. 67.) But, more frequently, they are written in a single line called, the Guida—headed by some old proverb, or well-known quotation from Holy Scripture, which, though ostensibly vouchsafed for the purpose of giving the student some little insight into the secret of their construction, tends rather, as a general rule, to increase his perplexity. Headings, such as these, are called Inscriptions: and so obscure is their occasional meaning, that even Glareanus calls one of them τῆς σφιγγὸς αἴνεγμα.
Foremost among the composers of these ingenious works, and high above them all, stands Josquin des Prés, the refinement of whose scholarship is as clearly proved, by the grace of his Motti, as his quite exceptional genius is by the smooth flow of the Canons to which they are prefixed. In the second Agnus Dei of his 'Missa L'Ami baudichon,' he intimates that the Tenor is to be silent, by the pretty Inscription, 'Agnus secundum non est cum grege.' In another place, he veils the same meaning under the Greek proverb, βάτραχος ἐκ Σερίφον, in allusion to Ælian's statement that the frogs on the Island of Seriphos do not croak. Other writers have contented themselves with 'Vox faucibus hæsit.'
To shew that the second Voice is to begin at the end, and sing backwards, Hobrecht says, plainly enough, 'Ut prius, sed dicitur retrograde.' Pierre de la Rue more sternly exclaims, 'Vade retro, Sathanas.' Another quaint old Composer writes, 'Canit more Hebræorum'; referring to the custom of reading Hebrew from right to left. Josquin sums up the whole matter in a single word—'Cancriza,' i.e. walk like a crab. Equally terse is the motto prefixed to the third Agnus Dei in his 'Missa L'Omme armé'; where the omission of all rests, in one of the parts, is indicated by the direction 'Clama ne cesses.' Sometimes he gives us a French motto, as in his 'Missa de Beata Virgine,' where 'Vous jeunerez les quatre temps' shews that one part is to wait four semibreves, before taking up the Subject—a direction which is less poetically expressed by another writer, in the words 'Fuga in epidiapason, post duo tempora'—'a Canon in the Octave above, after two Semibreves.'
Some of Hobrecht's Inscriptions are very obscure. 'Accidens potest inesse et abesse præter subjecti corruptionem' implies that the part may be sung, or omitted, at will, without injury to the music. 'Decimas reddo omnia quæ possideo' shews that the (unwritten) Bass must sing a Tenth below the Discant. 'Tu tenor cancriza, et per antifrasin canta' indicates that the Tenor is to sing backwards, and, with all the intervals inverted. Not less oracular is Mouton's 'Duo adversi adverse in unum,' which means that two singers are to stand opposite each other, with the Canon between them, each reading it upside down from the other's point of view—an arrangement which is also dictated by 'Respice me, ostende mihi faciem tuam.' More mysterious still is 'Justitia et Pax osculatæ sunt'—indicating that the two performers are to begin at opposite ends, and meet in the middle.
When black notes are to be sung in the time of white ones, we sometimes find 'Nigra sum, sed forrnosa'; or, 'Noctem in diem vertere'; or, 'Dum habetis lucem credite in lucem.' By 'Crescit in duplum' (or 'triplum') we understand that the notes are to be sung in Double (or Triple) Augmentation. 'Tres dent sex voces' means, that each of the three written parts is to be doubled, in Canon, so as to form a composition for six Voices.
The list of these hard sayings is interminable; and the hardness of many of them is increased by the Signs of Mode, Time, and Prolation, with which they are sometimes accompanied. For instance, a Semicircle, a Semicircle with a Bar drawn through it, and a Circle with a Point in the centre, would, if placed one above the other, at the beginning of a Stave, serve to indicate that one Voice was to sing four Crotchets in a Bar, another, four Minims, and the third, three Semibreves. In the last Agnus Dei of Pierre de la Rue's 'Missa L'homme armé,' we find a combination of no less than four such Signs.
Following the example of Palestrina, the great Composers of the 'Golden Age' cast all these pedantries aside, and wrote their really beautiful Canons in notation which any singer could readily understand. Palestrina himself delights in making two Voices sing in Canon, while three or four others carry on the Subject in close Imitation, or complicated Free Fugue; as in the lovely second Agnus Dei of his 'Missa Brevis,' and many others, equally beautiful. In all these cases, the Voices to which the Canon is committed are expected to sing from a single part; but, the Inscription prefixed to that part is so plain, that they find no difficulty whatever in doing so. Thus, 'Symphonizabis' (Missa Brevis as above) indicates a Canon in the Unison. 'Canon in Diapason' or 'Epidiapason,' a Canon in the Octave above, and so on. The sign, 
, or some similar figure—called the Presa—indicates the place at which the second Voice is to begin; and a pause, 
is placed over the note on which it ends. The two Voices can, therefore, sing just as easily from a single part, as from two separate copies.