292 Gersonides, Levi ben Gershom
worked zealously for the calling of the Council of CON-
STANCE(1414–18). There he led the successful drive to
end the schism, with the council deposing the rival popes
and electing Martin V (r. 1417–31). He also favored the
execution of John HUS. At the same time he alienated
much of the council by his persistent justification of the
rights of the Gallican or French National Church and his
demand for the condemnation of Jean Petit (1360–1411).
Petit had written a tract asserting that the assassination of
the duc d’Orléans by the partisans of the duke of Bur-
gundy was justifiable tyrannicide. The council did not
condemn Jean Petit. Threatened by the duke of Burgundy,
Gerson fled to VIENNA, where he wrote his Consolation of
Theologyin the tradition of BOETHIUS. Eventually permit-
ted to return to FRANCE, he spent his last days at LYON
teaching children and writing devotional works and
hymns. He died there on July 12, 1429.
ACHIEVEMENTSJohn Gerson was an outstanding advocate of conciliar
theories, writing that the authority of the universal
church represented by a general council was greater
than that of the pope; therefore, a legitimate general
council could depose and elect popes. A proponent of
Gallicanism or the power of the French Crown over the
clergy, he supported a strong monarchy with great influ-
ence on the church in France. An Ockhamist in PHILOS-
OPHY and theology, he gave great attention to the
pastoral care of women and the education of children.
He wrote a tract attempting to save JOANof Arc. He was
attracted by pseudo-Dionysian spirituality and the MYS-
TICISMof the DEVOTIOMODERNA, while following the
late medieval trend against an overly rational investiga-
tion of the faith.
See alsoWILLIAM OFOCKHAM.
Further reading:Jean Gerson, Jean Gerson: Early
Works,trans. and ed. Brian Patrick McGuire (New York:
Paulist Press, 1998); D. Catherine Brown, Pastor and
Laity in the Theology of Jean Gerson(New York: Cam-
bridge University Press, 1987); G. H. M. Posthumus
Meyjes, Jean Gerson, Apostle of Unity: His Church Politics
and Ecclesiology, trans. J. C. Grayson (Leiden: Brill,
1999); John B. Morrall, Gerson and the Great Schism
(Manchester: Manchester University Press, 1960); Louis
Pascoe, Jean Gerson: Principles of Church Reform(Leiden:
Brill, 1973).
Gersonides, Levi ben Gershom(Ralbag, Master Leo
of Bagnols)(1288–1344)Jewish exegete, philosopher,
Talmudist, mathematician, astronomer, scholar
Levi Ben Gershom was born in 1288. He lived in south-
ern France in PROVENCE, mainly at Orange and AVI-
GNON, where he was in touch with the papal court. In
the field of PHILOSOPHY, Gersonides’s contribution was
remarkable. His important Book of the Wars of the Lord
was a systematic attempt to analyze several fundamental
themes in THEOLOGY, such as the immortality of the soul,
prophecy, providence, and creation, using the conceptual
tools provided by ARISTOTELIANISM,MAIMONIDES, and
IBN RUSHD (Averroës). His thought can be viewed as
more rigorous and more creative than that of Mai-
monides. A part of the Book of the Wars of the Lordwas a
treatise on astronomy, often to be copied separately and
eventually translated into LATIN. His astronomical work
also included a treatise, dedicated to Pope CLEMENTVI,
on a scientific instrument invented by him to determine
the angular distance between stars. We also owe to him a
treatise on Aristotle’s LOGICand a set of commentaries on
the commentaries of Ibn Rushd. His biblical commen-
taries on Job, the SONG OFSONGS, Ecclesiastes, Esther,
Ruth, the Pentateuch, the historical books, Daniel, and
Proverbs were classics of Jewish exegesis and were incor-
porated into the annotated BIBLES. His ideas on the eter-
nity and creation of the world, God’s foreknowledge, and
free will were attacked by later rabbinic authorities. He
died in 1344.
Further reading:Levi ben Gershom, Gersonides’ The
Wars of the Lord, Treatise Three: On God’s Knowledge,trans.
Norbert Max Samuelson (Toronto: Pontifical Institute of
Mediaeval Studies, 1977); J. David Bleich, Providence in
the Philosophy of Gersonides(New York: Yeshiva Univer-
sity Press, Department of Special Publications, 1973);
Bernard R. Goldstein, The Astronomical Tables of Levi ben
Gerson(Hamden: Archon Books, 1974); Jacob J. Staub,
The Creation of the World according to Gersonides(Chico:
Scholars Press, 1982).Ghana Ghana formed an empire in black AFRICAin
the basin of the Niger River. In the third century tribes
near the medieval and modern city of TIMBUKTUwere
united under the rule of the Ghana clan, whose mem-
bers could travel in caravans, passing through Sudan
and the Sahara all the way to the Roman Empire. Ghana
gradually developed as this ruling dynasty imposed its
rule on the tribes of western Sudan in the valley of the
Senegal River. Little is known of its history. Archaeolog-
ical evidence has shown that the empire achieved a high
degree of civilization in the eighth century. The ARAB
conquest of North Africa, however, pushed BERBER
tribes to migrate southward. In the ninth and 10th
centuries, they threatened Ghana. Its rulers organized a
fierce defense and the resulting clashes were successful
and they began to expand northward, conquering some
Berber regions. In 990 the empire reached the zenith of
its expansion with the conquest of the Berber principal-
ity of Mauritania. The entire western Sudan fell under
Ghanian rule, marking the victory of settled over
nomadic peoples.
According to the secondhand testimony of an Arab
traveler, AGRICULTUREwas highly developed in the 11th