New Worlds and Th eir Challenges 109activities where there was so little pre ce dent. In this regard, much more
was to come.Dividing the World
Th e popes took an interest in these endeavors, especially those along
the west coast of Africa. Th ey even claimed the right to grant out these ter-
ritories—an assertion supported by Bartolus of Sassoferrato. His Tr e a t i s e
on Islands contended that the popes had jurisdiction over all islands not
adjacent to determined countries. Clement VI’s exercise of this right, re-
garding the Canary Islands, occurred during Bartolus’s lifetime. Papal in-
volvement in the exploration pro cess continued in the following century.
In 1452, Pope Nicholas V, in the bull Dum Diversas (“Until Diff erent”), au-
thorized Portugal to subjugate infi dels, conquer their kingdoms, and re-
duce them to slavery.
Th ree years later, in 1455, Nicholas V followed this up with another bull,
Romanus Pontifex (“Roman Priest”). Th is granted to Portugal “the right of
conquest” of a somewhat vaguely defi ned portion of Africa extending
through “all Guinea and beyond toward that southern shore.” Th e king of
Portugal was given the right “to invade, search out, capture, vanquish, and
subdue all Saracens and pagans whatsoever, and other enemies of Christ
wheresoever placed... and to reduce their persons to perpetual slavery.” He
was also authorized to legislate and to levy taxes in the area. Trade with
Saracens was permitted except in materials useful for war. Penalties for in-
fringement of this grant were specifi ed: excommunication for individuals,
interdict for communities. Th e following year, Pope Callixtus III, in a bull
entitled Inter Caetera (“Among Other [Works]”), reaffi rmed Nicholas V’s
grant and supplemented it by giving sole ecclesiastical jurisdiction over the
area to the Order of Jesus Christ (a military order, of which Prince Henry
was governor).
Rivalry between Spain and Portugal continued. Sometimes, it proved pos-
sible to resolve, or at least alleviate, it by means of bilateral agreements. A no-
table example was the Treaty of Aloaçoves in 1479. Portugal fi nally dropped
its claim to the Canary Islands in favor of Spain, with Spain in return con-
ceding Portugal’s title to Guinea, as well to the Cape Verde Islands, Madeira,
and the Azores. Th e treaty was approved two years later by Pope Sixtus IV.