Giles of Rome [Aegidius Romanus, Aegidius Colonna, Columna] (c1247-1316)
Giles of Rome was the most significant theologian of the Order of the Augustinian
Hermits in the 13th century. His exact date of birth is uncertain, just as is his traditionally
alleged relation to the noble family of the Colonna (which is not mentioned in
contemporary sources). He entered the Augustinian order at a young age, about 1260.
Later he was sent to study in Paris, where he probably was among the students of Thomas
Aquinas from 1269-1272, and started writing his commentary on Peter Lombard’s
Sentences, as well as extensive commentaries on Aristotle’s works. If one can believe the
traditional, yet often debated attribution, it was also during this period, around 1270, that
he composed the compilation of the philosophically doubtful and theologically
condemnable philosophical positions of Aristotle, Averroës, Avicenna, Algazel, Alkindi,
and Rabbi Moses (Maimonides), De Erroribus Philosophorum. This work was very much
in agreement with the spirit of the 1270 condemnations issued by Stephen Tempier, the
Bishop of Paris. Nevertheless, in 1277, Tempier’s zeal found even Giles’ doctrine suspect
on several counts, although the procedure against Giles was independent from the famous
condemnations of March 7 of the same year, directed against the “Latin Averroists” or
“Heterodox Aristotelians”. But Giles’ troubles did not prevent the king, Philip III, from
entrusting him with the education of his son, the future Philip the Fair. Giles’ immensely
influential political work, De Regimine Principum, dates from this period, and is
dedicated to his royal student. By 1281 Giles returned to Italy, where he started to play an
increasingly important role in his order. Yet, in 1285, upon the re-examination of his
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teachings, Pope Honorius IV asked him to make a public retraction of some of his theses
condemned in 1277. The retraction regained for Giles his license to teach, and so in effect
it only enabled him to exert an even greater influence in his order and beyond. As a
result, the general chapter of the Augustinian Hermits held in Florence in 1287 practically
declared his teachings the official doctrine of the order, commanding its members to
accept and publicly defend his positions. After serving in further, increasingly important
positions, in 1292 Giles was elected superior general of his order at the general chapter in
Rome. Three years later, in 1295, the new pope, Boniface VIII, appointed him archbishop
of Bourges. As an Italian archbishop in France, and a personal acquaintance of the parties
involved, Giles had a difficult role in the conflict between Philip the Fair and Boniface
VIII, but on the basis of his theological-political principles, he consistently sided with the
pope. On the other hand, after Boniface’s death, he supported the king’s cause against the
Order of Templars. In the subsequent years Giles continued to be active in the theological
debates of the time, until his death on December 22, in 1316, at the papal Curia in
Avignon.
Giles’ significance in the history of astronomy lies in his metaphysical
investigations into some fundamental physical notions, such as those of matter, space,
and time. These investigations, although usually carried out under the pretext of merely
providing further refinements of traditional positions, in fact opened up a number of new
theoretical dimensions, pointing away from traditional Aristotelian positions.
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For example, Giles’ interpretation of the doctrine of the incorruptibility of
celestial bodies does not rely on the traditional Aristotelian position of attributing to them
a kind of matter (namely, ether, the fifth element, quintessence) that is radically different
from the matter of sublunary bodies (which were held to be composed of the four
elements, namely, earth, water, air, and fire). Since matter according to Giles is in pure
potentiality in itself, it certainly cannot make a difference in the constitution of celestial
bodies. Therefore, he argues that what makes the difference is that the perfection of the
determinate dimensions of these bodies, filling the entire capacity of their matter, renders
their matter incapable of receiving any other forms, and that is why they are
incorruptible. These determinate dimensions are to be distinguished from the
indeterminate dimensions of matter (dimensiones interminatae), the dimensions
determining a quantity of matter that remains the same while matter is changing its
determinate dimensions in the constitution of an actual body, as in the processes of
rarefaction and condensation. The distinction is necessitated by considering that if matter
is non-atomic, but continuous, genuine rarefaction or condensation (i.e., diminution or
enlargement of the actual, determinate dimensions of the same body without the
subtraction or addition of any quantity of matter) can take place only if the changing
actual dimensions are distinct from the constant quantity of matter. This interpretation of
Averroes’ notion of dimensiones interminatae as the invariable quantity of matter can be
regarded as taking a significant step toward the modern notion of mass.
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Similar considerations apply to Giles’ metaphysical investigations into the nature
of time. Motivated by the Aristotelian argument against the possibility of a vacuum on
the grounds that free fall in a vacuum would have to be instantaneous, in his hypothetical
speculations concerning the possibility of instantaneous motion in a vacuum, Giles
transformed the Aristotelian notion of time into a more general idea of a succession of
instants, which enabled him to distinguish different orders of time, namely, the proper
time of the thing moved, which is the intrinsic measure of its successive motion (mensura
propria), and celestial time, which is the extrinsic measure (mensura non propria) of the
same motion. Thus, it would be possible for a thing instantaneously moved in a vacuum
to cover all intervening spaces successively at different instants of its proper time, which,
however, being unextended and not separated by time, may coincide with the same
instant of celestial time. This more general notion also enabled Giles to distinguish
between time that is the mode of existence of material things, and angelic time, which is
the mode of existence of non-material, yet not simply eternal beings.
Gyula Klima
Fordham University
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Bibliography
Primary Literature
Aegidii Romani Opera omnia, Firenze: Leo S. Olschki, 1985Aegidii Romani Quodlibeta, Frankfurt/Main: Minerva, 1966
Aegidii Romani Quaestiones in Octo Libros Physicorum Aristotelis, Frankfurt/Main:
Minerva, 1968
Aegidii Romani Quaestio de Materia Coeli, Frankfurt/Main: Minerva, 1982
Secondary Literature
Del Punta, F. -- Donati, S. -- Luna, C. 1993: “Egidio Romano”, in Dizionario Biografico
degli Italiani, vol. 42, Roma: Istituto della Enciclopedia Italiana, pp. 319-341.
Donati, S.: “La dottrina di Egidio Romano sulla materia dei corpi celesti. Discussioni
sulla natura dei corpi celesti alla fine del tredicesimo secolo”, Medioevo,
12(1986), pp. 229-280.
Donati, S.: “La dottrina delle dimensioni indeterminate in Egidio Romano”, Medioevo
14(1988), pp. 149-233.
Donati, S.: “Ancora una volta sulla nozione di quantitas materiae in Egidio Romano”,
Knowledge and the Sciences in Medieval Philosophy: Proceedings of the
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Eighth International Congress of Medieval Philosophy (SIEPM), II, edd. S.
Knuttila- R. Työrinoja -- S. Ebbesen, Helsinki: Luther-Agricola Society, 1990.
Trifogli, C.: “The Place of the Last Sphere in Late-Ancient and Medieval
Commentaries”, Knowledge and the Sciences in Medieval Philosophy.
Proceedings of the Eighth International Congress of Medieval Philosophy
(SIEPM), II, edd. S. Knuttila-- R. Työrinoja -- S. Ebbesen, Helsinki: LutherAgricola Society, 1990, pp. 342-350.
Trifogli, C.: “La dottrina del tempo in Egidio Romano”, Documenti e studi sulla
tradizione filosofica medievale, 1(1990), pp. 247-276.
Trifogli, C.: “Egidio Romano e la dottrina aristotelica dell’infinito”, Documenti e Studi
sulla tradizione filosofica medievale, 2(1991), pp. 217-238.
Trifogli, C.: “Giles of Rome on Natural Motion in the Void”, Medieval Studies 54(1992),
pp. 136-161.
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