he inclined toward the melodically, rhythmically, and
harmonically smoother style cultivated from the 1430s
onward; and what appear to be his last Marian antiphons
are as forward-looking as anything of the period. Most
of these more modern-sounding works are preserved
only in continental sources, and doubtless there is further
music by Leonel among the many anonymous pieces in
the earlier Trent Codices and other mid-century conti-
nental manuscripts.
Leonel’s short treatise in the vernacular “for hem that
wilbe syngers or makers or techers” provides a lucid
explanation of improvised counterpoint, especially as
it involves boys’ voices.
See also Dunstable, John
Further Reading
Primary Sources
Hamm, Charles, ed. Leonel Po w e r: Complete Wo r k s. Corpus
Mensurabilis Musicae 50. Rome: American Institute of
Musicology, 1969
Hughes, Andrew, and Margaret Bent, eds. The Old Hall Manu-
script. 3 vols. in 4. Corpus Mensurabilis Musicae 46, Rome:
American Institute of Musicology, 1969–73
Meech, Sanford B. “Three Musical Treatises in English from
a Fifteenth-Century Manuscript.” Speculum 10 (1935):
235–69.
Secondary Sources
Bent, Margaret. “Power, Leonel.” NGD 15:174–79
Bowers, Roger D. “Some Observations on the Life and Career of
Lionel Power,” Proceedings of the Royal Musical Association
102 (1975–76): 103–27.
Gareth Curtis
PROSDOCIMUS DE BELDEMANDIS
(d. 1428)
Prosdocimus de Beldemandis (Prosdocimo de’ Beldo-
mandi), was the author of treatises on arithmetic, geom-
etry, astronomy, and music. After studying in Bologna,
he took a doctorate in arts at Padua on 15 May 1409 and
received a license in medicine there on 15 April 1411.
He was a professor of arts and medicine at Padua from
1422, at the latest, until his death.
Prosdocimus wrote on all four of the quadrivial arts;
the following treatises have survived. On arithmetic:
Canon in quo docetur modus componendi et operandi
tabulam quandam (Padua, 1409 or 1419) and Algorismus
de integris sive pratica arismetrice de integris (Padua,
1410). On geometry: De parallelogramo. On astronomy:
Brevis tractatulus de electionibus secundum situm lune
in suis 28 mansionibus (Montagnana, 1413); Scriptum
super tractatu de spera Johannis de Sacrobosco (Padua,
1418); Canones de motibus corporum supercelestium
(Padua, 1424); Tabule mediorum motuum, equationum,
stationum et latitudinum planetarum, elevationis signo-
rum, diversitatis aspectus lune, mediarum coniunctio-
num et oppositionum lunarium, feriarum, latitudinum
climatum, longitudinum et latitudinum civitatum; Stelle
fi xe verifi cate tempore Alphonsi; Canon ad inveniendum
tempus introitus solis in quodcumque 12 signorum
in zodiaco; Canon ad inveniendum introitum lune in
quodlibet signorum in zodiaco; Compositio astrolabii;
and Astrolabium. On music: Expositiones tractatus
pratice cantus mensurabilis Johannis de Muris (Padua,
possibly 1404); Tractatus pratice cantus mensurabilis
(1408); Brevis summula proportionum quantum ad
musicam pertinet (1409); Contrapunctus (Montagnana,
1412); Tractatus pratice cantus mensurabilis ad modum
Ytalicorum (Montagnana, 1412); Tractatus plane mu-
sice (Montagnana, 1412); Parvus tractatulus de modo
monacordum dividendi (Padua, 1413); and Tractatus
musice speculative (1425).
Prosdocimus based his Algorismus de integris on a
similarly titled work of the thirteenth-century polymath
Johannes de Sacrobosco; his Scriptum super tractatu de
spera Johannis de Sacrobosco is based on the same au-
thor’s textbook of Ptolemaic astronomy, one of the most
widely disseminated medieval astronomical works.
Prosdocimus’s musical treatises represent an at-
tempt to survey the entire discipline; no earlier music
theorist had attempted such a comprehensive project
through separate treatises on the subdisciplines, and
Prosdocimus’s musical writings are of great importance
because of their scope and clarity. In Parvus tractatulus
de modo monacordum dividendi, he described a scale
that preserved the standard medieval “Pythagorean”
tuning (i.e., with pure perfect fi fths, slightly wider
than those of present-day equal temperament) but with
seventeen notes to the octave (seven naturals, fi ve fl ats,
and fi ve sharps not quite in tune with the fl ats); this ex-
panded scale may have been an important step toward
the tempered tunings of the later fi fteenth century. In
Contrapunctus, he confi rmed that medieval scribes did
not write all the accidentals they necessarily expected to
be performed, and he gave rules that clarify where ac-
cidentals are appropriate, even if unwritten. He surveyed
the theory of rhythmic mensuration in three treatises,
Expositiones tractatus pratice cantus mensurabilis Jo-
hannis de Muris (a commentary on the Libellus cantus
mensurabilis, the most widely disseminated medieval
treatise on mensuration, which laid the foundation for
French fourteenth-century rhythmic notation); Trac-
tatus pratice cantus mensurabilis, his own account of
fourteenth-century French mensuration; and Tractatus
pratice cantus mensurabilis ad modum Ytalicorum, an
exposition of contemporaneous Italian mensuration (this
is the most comprehensive treatment of Italian mensura-
tion in its mature stage). Tractatus musice speculative is
an attack on the division of the tone into fi fths described
a century earlier by Marchetto da Padova, based on whatPROSDOCIMUS DE BELDEMANDIS