Keeping Kings in Check 85(such as the position of persons who were vassals of two lords at war with
one another).
Bonet’s work was in turn followed up— and largely replicated— by Chris-
tine de Pisan in the early fi ft eenth century. Of Italian family origin, Chris-
tine grew up in France, where her father served as a physician and astrologer
to King Charles V (of whom Christine would later write a noted biography).
She is now remembered largely for her concerns about the position of women
in medieval society. Her contribution to international law was a book enti-
tled Feats of Arms and Chivalry, written around 1410. As a self- proclaimed
“simple little woman,” she modestly invoked the aid of Minerva, the Roman
goddess of both wisdom and war. Her debt to Bonet was evident in an un-
conventional manner, through a vision of him. She proceeded to recapitu-
late the writing of her “dear friend” and “dear master” (though it is not
likely that they ever met), even following closely the order of topics covered
by Bonet. Later in life, she retired to a convent.
Th e largest body of medieval practice concerned prisoners of war, an area
in which it is possible to report some progress. Th e ancient practice of en-
slaving prisoners of war (or simply killing them) fell into disuse, at least in
confl icts between Christian powers—“according to the customs of modern
times,” as John of Legnano explained. In its place, a system of ransoming
prisoners grew up, which, over the course of time, became extremely elabo-
rate. Th e subject of ransoms, in fact, provides one of the most striking il-
lustrations of the legalistic medieval mind in action. In general, a prisoner
was regarded as belonging to the individual soldier who captured him. Th e
captor and the prisoner would then proceed to negotiate ransom terms,
which were oft en reduced to writing. Th e standard arrangement was that the
prisoner would promise to pay an agreed amount of money to the captor,
perhaps in periodic installments. He would typically promise to be a good
and loyal captive, in a manner resembling the swearing of vassalage in feudal
arrangements. Agreements sometimes contained details of the treatment of
the prisoner— with the captive having a legal action against his captor (at least
in theory) in the event of a breach.
Th e ransom amounts naturally varied with the rank of the captive. When
King David II of Scotland was captured by the En glish at the Battle of Neville’s
Cross in 1346, for example, the ransom sum (agreed aft er eleven years) was for
some £66,000. Th e literary fi gure Geoff rey Chaucer, in contrast, following his