84 Law and Morality Abroad (to ca. ad 1550)weapons against Christians. Th eir use continued to be allowed against in-
fi dels and pagans. Th e in eff ec tive ness of this prohibition, however, was evi-
dent in the deadly use of archers by the En glish against the French during
the Hundred Years War in the fourteenth and fi ft eenth centuries, as well as
in the continued use of crossbows by various armed forces.
In addition to these contributions of the Catholic Church, various cus-
tomary practices grew up concerning warfare. Declarations of war are an
instructive illustration. Th e making of a formal declaration at the outset of
a war was not, as such, among the requirements for a just war in medieval
just-war doctrine. Nor was there any strong sense of anything called a state
of war. Nevertheless, it was the practice of the Eu ro pe an states to make some
kind of formal declaration or gesture to the opposing side at the commence-
ment of a war. It might be a declaration conveyed by means of a herald (a
professional offi cial messenger), or it might consist of some dramatic sym-
bolic act, such as the throwing down of a gauntlet (or glove).
Not until the fourteenth century was an attempt made at a comprehen-
sive summa of the laws of war. Th is was by a prominent Italian jurist named
John of Legnano, who taught both civil and canon law at the University of
Bologna. His Treatise Concerning War, Reprisal and the Duel, written in
1360, may be regarded, with some allowances, as the very fi rst important
book in Western civilization on international law. He was said to have been
stimulated to write it by the vivid personal experience of being present in
Bologna during a siege.
It was, however, a pop u lar ized version of John’s treatise that achieved the
wider circulation in the Middle Ages. Th is was written by a Provençal monk
named Honoré Bonet (or Bouvet). Bonet spent several years in Avignon, in
close contact with the university there, as well as with Pope Clement VII. He
also served as prior of a monastery and qualifi ed as a doctor of canon law.
His book, entitled Th e Tree of Battles, was published in 1387 and dedicated
to King Charles VI of France (for whom he later undertook some diplo-
matic ser vices). Largely a summation of John of Legnano’s exposition, the
book treated a host of practical questions arising in war, such as strategy,
or ga ni za tion, and preparation. It also covered a range of legal topics, in-
cluding the entitlement of soldiers to wages and indemnities, issues of ran-
soms, questions regarding truces and wagers of battle (set- piece contests by
appointed champions), and various puzzles arising from multiple loyalties