Quintus Caecilius Iucundus is one of the stars of the Cambridge Latin Course series of books, set in the Ancient Roman Empire. He was the son of wealthy banker Lucius Caecilius Iucundus and his wife Metella, all of whom were real people and who lived in Pompeii before 79 AD.
In Book One, the reader finds Quintus as a mischievous teenager in Pompeii in the year before it is destroyed by the volcano Mount Vesuvius. As Caecilius is dying, he sends his slave Clemens to find Quintus, and give him the rights to Caecilius' property and fortune.
In Book Two, the reader finds Quintus in Roman Britain, living with his cousin Salvius, who is also a real historical figure. They enjoy several adventures together and with other inhabitants of Britain. The book then travels back in time to Alexandria, in Roman Egypt, where Quintus frees his slave Clemens and befriends Barbillus, a very rich Roman.
In Book Three, Quintus and Salvius become enemies, as Salvius plots to kill a friend of Quintus'. Salvius accuses Quintus of treason, but Quintus follows his moral compass and attempts to foil the murder. The book then goes back in time to Rome, where Quintus is not present. Quintus does not appear again until the last stories of Book Five when his old friend Salvius goes on trial.