Complex sentence: Antonius arrives to Herculenum and informs Glaucus and Ascanius of his discovery as proof he tells them that the treasures stolen from the citizen of Pompeii are hidden in the temple of Isis.
Split into simpler sentences: Antonius arrives to Herculenum and informs Glaucus and Ascanius of his discovery. As proof he tells them that the treasures stolen from the citizen of Pompeii are hidden in the temple of Isis.