th century, till under the new Royal House of Aviz, in the
boyhood of Henry the Navigator, this maritime and commercial element
had clearly become the most important in the State, the main interest
even of Government.

So, from the first mercantile treaty of 1294, between the traders of
Lisbon and London, we feel ourselves beyond the mere fighting period,
and before the death of Diniz (1325), there is a good deal more progress
in the same direction. The English treaty of exchange is followed by
similar ones with France and with Flanders, while for the protection of
this commerce, as well as to prove his fellowship or his rivalry with
the maritime republics of Italy, Diniz,[32] the "Labourer King," built
the first Portuguese navy, founded a new office of state for its
command, and gave the post to a great Genoese sailor, Emanuel Pessanha,
1317. With the new Lord High Admiral begins the Spanish-Italian age of
ocean voyages, and the rediscovery of the Canaries in 1341 is the first
result of the alliance. In 1353 the old treaty of 1294 is enlarged and
safeguarded by fresh clauses signed in London, as if to guard against
future trouble in the dark days then hanging over Portugal.

[Footnote 32: See Note 2, page 137.]

For the next generation (1350-1380), the national politics are bound up
with Spanish intrigues and lose nearly all reference to that larger
world, to which the kingdom was recalled by the Revolution of 1383, the
overthrow of Castille on the battle-field of Aljubarrota, and the
accession of John of Aviz. Once more intensely, narrowly national, one
might almost say provincial, in peninsular matters, Portugal then
returned to its older ambition of being, not a make weight in Spanish
politics, but a part of the greater whole of commercial and maritime
Europe. Almost ceasing to be Spanish, she was, by that very transfer of
interest from land to sea, fitted for her special part,--

"to open up those wastes of tide
No generation opened before."

It was through a love affair that the crisis came about. Ferdinand the
Handsome, the last of the House of Burgundy to reign in Lisbon, became
the slave of the worst of his subjects, the evil genius of himself and
his kingdom, Leonora Telles. For her sake he broke his marriage treaty
with Castille (1372), and brought down the vengeance of Henry of
Trastamara, whom the Black Prince of England had fought and seemed to
conquer at Navarette, but who in the end had foil