20 Ahl al-Kitab
Ages: Technology, Practice, and Representation(Philadel-
phia: University of Pennsylvania Press, 1995); B. H.
Slicher van Bath, The Agrarian History of Western Europe,
A.D. 500–1850, trans. Olive Ordish (London: Edward
Arnold, 1963); Andrew M. Watson, Agricultural Innova-
tion in the Early Islamic World: The Diffusion of Crops and
Farming Techniques, 700–1100(Cambridge: Cambridge
University Press, 1983).
Ahl al-Kitab(People of the Book, Possessors of the
Scripture)SeeDHIMMI.
Ailly, Pierre d’ (Peter, Petrus de Alliaco) (ca. 1350–
1420)French scholar, cardinal
Pierre d’Ailly was born about 1350 at Compiègne. He
spent most of his life in an association with the Univer-
sity of PARIS: as a graduate in theology from the College
of Navarre in 1380, master of the college in 1384, and
chancellor of the university in 1389.
One of the university’s chief concerns was the West-
ern SCHISM(1378–1417), in which two and later three
rival popes claimed legitimacy. At first d’Ailly supported
the Avignon pope Benedict XIII (r. 1394–1417), but he
soon became a radical leader of the conciliar movement in
- The Conciliarists argued that a general council of
the church supersedes the power of the pope and could
therefore end the schism by choosing a new pope satisfac-
tory to all parties. D’Ailly played a prominent part at the
Council of Pisa in 1409, which elected a new pope,
Alexander V (r. 1409–10). In 1411 Alexander’s successor,
John XXIII (r. 1410–15), made d’Ailly a cardinal. When
the rival popes (Benedict and John) refused to resign,
however, the Council of CONSTANCE (1414–18) was
called. An acknowledged leader, d’Ailly helped effect the
decision to have the contending popes abdicate. The
council then elected a new pope, Martin V, and the schism
ended. D’Ailly himself became a candidate for the papal
throne, but he lost the election because of opposition from
France’s enemies, England and Burgundy. He retired for
safety to Avignon, where he served Martin V.
Pierre d’Ailly wrote prolifically. His works on the
nature of the church had the most lasting influence. He
developed further the theory of conciliarism and the con-
cept that the only infallible body in the church is the
whole of the faithful. He was an advocate of calendar
reform and took great interest in ASTROLOGY. His book on
GEOGRAPHY,The Image of the World,was read carefully by
COLUMBUS, who said that it inspired his voyage of 1492
by suggesting the feasibility of sailing from Spain west to
India. D’Ailly also wrote on astronomy, meteorology,
mathematics, logic, metaphysics, and psychology. He died
in Avignon in 1420.
Further reading:Pierre d’Ailly, Imago Mundi,trans.
E. F. Keever (Wilmington: Linprint, 1948); Francis Oakley,
The Political Thought of Pierre d’Ailly(New Haven, Conn.:
Yale University Press, 1964); Bernard Guenée, Between
Church and State: The Lives of Four French Prelates in the
Late Middle Ages(Chicago: University of Chicago Press,
1991); Laura Smoller, History, Prophecy, and the Stars: The
Christian Astrology of Pierre d’Ailly, 1350–1420(Princeton,
N.J.: Princeton University Press, 1994).Aistulf(749–756)king of the Lombards
When Aistulf was proclaimed king in northern Italy in
749, Pavia was held by his brother and predecessor,
Ratchis (r. 744–749), who soon retired to the Abbey
of MONTECASSINO. The ambitious Aistulf reorganized
Lombard military service according to wealth. He began
the conquest of Byzantine and papal territories in Italy.
He occupied RAVENNAand initiated an alliance of Spole-
tan and Beneventan Lombards against Rome. He sub-
jected the papal city of Rome to tribute in 752 and even
besieged it in 756. In the meantime Pope Stephen II (r.
752–57) had obtained help from the FRANKS.PÉPINIII
THESHORTdefeated Aistulf in 755 and 756 and obliged
him to give the conquered territories to the pope, includ-
ing the Exarchate of Ravenna, much to the anger of
the Byzantine Empire. When Aistulf died accidentally in
756, an alliance between the Lombards and the Byzan-
tines was under negotiation.
Further reading: Neil Christie, The Lombards
(Oxford: Blackwell, 1995); Jan T. Hallenbeck, Pavia and
Rome: The Lombard Monarchy and the Papacy in the Eighth
Century (Philadelphia: American Philosophical Society,
1982); Peter Llewellyn, Rome in the Dark Ages(London:
Faber and Faber, 1971); Thomas F. X. Noble, The Republic
of St. Peter: The Birth of the Papal State, 680–825
(Philadelphia: University of Pennsylvania Press, 1984).alabaster Alabaster is a dense, translucent hydrated
calcium sulfate, a form of gypsum used by sculptors for
small panels, figures and tombs on the Continent and in
England. Evidence from English panels indicates that
medieval carvers initially shaped the alabaster by saw.
Subsequent carving resembled woodcarving, using a
chisel or a knife. Deeper undercutting was done with a
small drill. The application of paint and gilding often fol-
lowed, and a smoothing by an abrasive of sand or pumice
completed the artifact.
Alabaster was popular in Germany during the 15th
century and England tombcarvers in particular used
alabaster from the beginning of the 14th century. Numer-
ous image panels and altarpieces were also carved. The
English alabaster industry also had a lively export trade,
and its products were sought throughout Europe.
Further reading:Francis Cheetham, “Alabaster,” Dic-
tionary of Art,1.515–520; Walter Leo Hildburgh, English
Alabaster Carvings as Records of the Medieval Religious
Drama(Oxford: Printed by Charles Batey for the Society
of Antiquaries of London, 1949); Francis Cheetham, The