The first he gave to the public was _Martianus Capella_.

This is one of those obscure authors, who are commonly not read till we have nothing else to learn: the title of his work is, _Of the marriage of Mercury and Philology, in two books; to which are annexed seven other books on the liberal arts_.
The author was an African, and his style, like that of most authors of his nation, obscure and barbarous; which makes it not easy to be understood.

Before this there was no good edition of his works.

John Grotius had put into his son's hands a manuscript of Capella: Hugo shewed it to Scaliger; and this learned man, whose counsels were commands to the young Grotius, engaged him to study that author, and publish a new edition of him.
Though Grotius was then but fourteen, the difficulty of the undertaking did not discourage him: he read all the works that had relation to the matters Capella treated of; and at length acquitted himself of the task enjoined him by Scaliger with such abilities and success, as, to use Mr.
Baillet's words, astonished the whole world.
The work appeared in 1599.

It would have been published before, but for his journey to France, and some delays occasioned by the bookseller.
Grotius also informs us, that he would have printed it sooner, had he been less taken up with the study of the law.
To judge of Grotius' labour it will be sufficient to read what he says in the preface.