Ars de Pulsatione Lambuti

Fragment of a treatise written in Granada by a moor named Fulan, dated 1495, on playing the “lambutum” presumably the lute but according to the author, applicable to other string instruments as well as the vihuela.

Sequitur ars de pulsatione lambuti, et aliorum similium instrumentorum, inventa a Fulan mauro regni Granate
Mirum est, ut dona sancti spiritus ipsis infidelibus infundantur. Ea propter hoc dico quoniam quidam Fulan nomine, maurus de regno Granate apud Yspanias inter Yspanos cytharistas laude dignus, per pulsatus spiritu scientie invenit artem dandam hiis qui diligunt pulsare lambutum, cytharam, violam et hiis similia instrumenta. Et dicit dictus Fulan quod, postquam bonus cytharista grupaverit suum instrumentum per bonam artem, attendendum est ubi sunt semythonia in ipso instrumento. Est eciam attendendum ubi sunt semythonia in cantilena ponenda in ipso instrumento. Et ponat tali modo cantilenam in instrumento, quod semythonia cantilene respondeant semythoniis instrumenti; alias autem in vanum laborat. Dicit denique dictus Fulan, quo domnis punctus, qui sit sine positione alicuis digitorum in grupis, est Alif in eorum littera, quod in nostra sonat A. Alphabetum ipsorum maurorum ego ponam per ordinem; verum ipsi mauri incipiunt in manu dextra, et tendunt versus sinistram. Nos vero latini cum grecis è contra, quoniam incipimus in sinistra et finimus in dextra. Sequitur alphabetum ipsorum maurorum …
Primus grupus post Alif in ipso instrumento est semythonium. Secundus grupus respondet ipsi Alif per thonum. Tercius grupus in instrumento respondet ipsi Alif cum thono et semythono. Quartus grupus debet correspondere ipsi Alif per duos thonos. Quintus grupus respondet ipsi Alif per duos thonos cum semythono, et sic faciunt dyathessaron. Sextus grupus distat ab Alif per tres thonos, et sic faciunt trithonum, Septimus grupus respondet ipsi Alif per tres thonos cum uno semythono, et faciunt dyapentam. Tu vero, David (loquitur Michael de Castellanis monachus ad Davidem monachum) pone alia plura: ego enim tedio aquarum multarum (que me scribere non permittunt) fessus sum.
Omnia ista de pulsacione lambuti ego habui a fratre Jacobo Salvá, ordinis Praedicatorum, filio den Bernoy (vel Banoy) de linariis, dioc. Barchin. qui caritate devictus revelavit mihi ista. Deus sit tibi merces. Amen.

fragment of a lute treatise from the late 15th century formerly in the monastery of the Padres Cupuchinos in Girona. The treatise is mentioned by Riaño in 1887 as lost (riano1887, 9). A more recent study has confirmed the disappearance of the original source (cortes2011, 45).
The only surviving passage form the treatise was copied by Father Jaime Villanueva (villanueva1803, v.14, pp. 176-178). Corona-Alcalde (personal communication, 2000) “speaks of the art of playing the ‘lambutum’, setting out the exposition of a system of tablature useful for lute, zither, viola and similar instruments, invented by the aforementioned Moor called Fulan”. The instruments are “lambutum, cytharam, violam”. Cytharam is probably not zither as Corona-Alcalde suggests. He concludes that it describes a system of tablature, but this is not thoroughly convincing. It describes fret placement on the lute, by intervallic distance, compared to a base note “a”. Corona notes that “The ‘lambutum’ is documented in the lists of instruments used in the processions of Gerona in 1455 (Barbieri papers), and thanks to Pierre Le Loyer, in his "Discours des Spectres et Apparitions d'Esprits" (Paris, 1605) we know that this instrument is the lute: "luth que les Grecs modernes appelent labouto" [original name in Greek letters]. Corona discusses the treatise at length in his book on the lute in Spain (corona2014, 32ff).
The following translation of the treatise is that of Farmer (farmer1930, 99-100):

It is marvellous that the gifts of the Holy Spirit should be poured down on infidels. I say this for the reason that a certain Fulan by name, Moor of the Kingdom of Granada, worthy of praise in Spain among Spanish guitarists, by the impulse of the spirit of learning, has discovered the art to be given to those who have an inclination for playing the lambutum, guitar, viol and instruments similar to these. And the said Fulan says that after a good guitarist has arranged (fretted) his instrument with skill, he must take care where the semitones are in the instrument itself. Attention must also be paid as to where the semitones are in the song which is to be played on the instrument itself. And he must place a song on an instrument in such a way that the semitones of the song correspond with the semitones of the instrument; otherwise he labours in vain. The said Fulan says further, that every note which may be without a position for any of the fingers in the frets is Alif (A) in their letters, which sounds A in ours. I shall place the alphabet of the Moors themselves in order; but the Moors themselves write from right to left. We Latins with the Greeks, on the contrary, write from left to right. Here follows the alphabet of the Moors …
The first fret after Alif in the instrument itself is a semitone. The second fret answers Alif by a tone. The third fret in the instrument answers Alif with a tone and semitone. The fourth fret ought to correspond to Alif by two tones. The fifth fret answers Alif by two tones with a semitone, and thus they make a diàtessáron. The sixth fret is distant from Alif by three tones, and thus they make a tritone. The seventh fret answers Alif by three tones with one semitone, and they make it a diàpente. But you, David, do the rest: for I am tired with the weariness of many waters (which prevent me from writing).
All these instructions for playing the lambutum I have from Brother Jayme Salvà. of the order of Preachers, son of Bernoy (or Banoy) of the linen weavers, in the diocese of Barchin. who, filled with kindness, has explained this to me. May God be your recompense.