The work, which involved the reconstruction of trade and navigation from its origins to the 18th century, remained incomplete, only 4 volumes dedicated to the pre-Roman, Greek and Roman periods were published. Dealing with navigation and commerce in its various aspects, historical, political, philosophical and juridical, only up to the time of Augustus, it is to be considered, as L. Bianchini pointed out: "of mere erudition, sometimes inaccurate, verbose and without scientific principles" . However, it played an important role in De Jorio's scientific and professional life, and he thus began to deal with a subject that he would never abandon, both as a magistrate and as a scholar and writer of law, history and economics. At the same time he attracted the attention and esteem of the Neapolitan government, which recognized his specific competence. The year following the release of the first volume, D., appointed member of the Academy of Sciences and Fine Letters, was commissioned by Ferdinand IV to draw up a maritime code.