Its outline is as follows: _Book I._ After invoking the muses and making a ceremonious address to King Sebastian, the poet describes how Jupiter, having assembled the gods on Mount Olympus, directs their glances upon Vasco da Gama's ships plying the waves of an unknown sea, and announces to them that the Portuguese, who have already made such notable maritime discoveries, are about to achieve the conquest of India.
Bacchus, who has long been master of this land, thereupon wrathfully vows Portugal shall not rob him of his domain, while Venus and Mars implore Jupiter to favor the Lusitanians, whom they consider descendants of the Romans.

The king of the gods is so ready to grant this prayer, that he immediately despatches Mercury to guide the voyagers safely to Madagascar.

Here the Portuguese, mistaken for Moors on account of their swarthy complexions, are at first made welcome.
But when the islanders discover the strangers are Christians, they determine to annihilate them if possible.

So, instigated by one of their priests,--Bacchus in disguise,--the islanders attack the Portuguese when they next land to get water.

Seeing his men in danger, Da Gama discharges his artillery, and the terrified natives fall upon their knees and not only beg for mercy, but offer to provide him with a pilot capable of guiding him safely to India.
This offer is accepted by Da Gama, who does not suspect this pilot has instructions to take him to Quiloa, where all Christians are slain.