The most significant literary work of Plutarch is, by common consensus, the Parallel Lives, which are parallel biographies, in pairs, of a Greek and a Roman politician or general, totaling 48, of which 46 have survived.

Of course, he also wrote the Moral Essays, numerous treatises on topics such as virtue, theology, religion, politics, and the role of philosophy in shaping the character, primarily of public men, whose choices and actions have always determined the lives of those in power. However, it seems that with his Moral Essays, he did not feel he achieved his objective of influencing people of his time and steering them toward the path of virtue, at a time when the Roman Empire was at its height and heading for an inevitable decline.

Thus, he turned to the biographies of great politicians and generals of the past, in order to provide more tangible and human examples – models for emulation of their great moments or for avoiding their unlawful activities. Among his foremost choices are Solon with Poplicola, Themistocles with Camillus, Aristides with Cato, Pericles with Fabius Maximus, Alcibiades with Marcus, Pelopidas with Marcellus, Alexander with Caesar, Agisilaus with Pompey, Demetrius with Antony, and others.

In the Parallel Lives, Plutarch clearly states that he does not write history nor does he focus his interest on recording their most prominent deeds, but through real individuals and true situations, he examines their inner world and provides readers with the necessary historical material for understanding the characters of these famous men and their moral behavior.

Thus, in a masterful way, Plutarch reflects and marries his knowledge of the past with the need for moral revival of peoples and rulers, at a time marked by signs of decay.