er," and by virtue of "the authority of omnipotent God
granted to us in St. Peter, and of the Vicarship of Jesus Christ which
we administer upon the earth."[544] It was a substantial reward for the
monarchs who had completed the overthrow of Mahometan rule in Spain, and
it afforded them opportunities for further good work in converting the
heathen inhabitants of the islands and mainland of Asia.[545]

[Footnote 544: "De nostra mera liberalitate, et ex certa
scientia, ac de apostolicae potestatis plenitudine." ...
"auctoritate omnipotentis Dei nobis in beato Petro concessa, ac
vicariatus Jesu Christi qua fungimur in terris." The same
language is used in the second bull. Mr. Prescott (_Ferdinand
and Isabella_, part i. chap, vii.) translates _certa scientia_
"infallible knowledge," but in order to avoid any complications
with modern theories concerning papal infallibility, I prefer
to use a less technical word.]

[Footnote 545: A year or two later the sovereigns were further
rewarded with the decorative title of "Most Catholic." See
Zurita, _Historia del Rey Hernando_, Saragossa, 1580, lib. ii.
cap. xl.; Peter Martyr, _Epist._ clvii.]

[Sidenote: Treaty of Tordesillas.]

On the following day Alexander issued a second bull in order to prevent
any occasion for quarrel between Spain and Portugal.[546] He decreed
that all lands discovered or to be discovered to the west of a meridian
one hundred leagues west of the Azores and Cape Verde islands should
belong to the Spaniards. Inasmuch as between the westernmost of the
Azores and the easternmost of the Cape Verde group the difference in
longitude is not far from ten degrees, this description must be allowed
to be somewhat vague, especially in a document emanating from "certain
knowledge;"[547] and it left open a source of future disputes which one
would suppose the "plenitude of apostolic power" might have been
worthily employed in closing. The meridian 25 deg. W., however, would have
satisfied the conditions, and the equitable intent of the arrangement is
manifest. The Portuguese were left free to pursue their course of
discovery and conquest along the routes which they had always preferred.
King John, however, was not satisfied. He entertained vague hopes of
finding spice islands, or something worth having, in the western waters;
and he wished to have the Li