For “what slave, what executioner”—as Bodin aptly describes this passion in On the Commonwealth, book 2, chapter 5—“can torture a condemned person as cruelly as this fear and suspicion? Fear of death, disgrace and torment are the furies and vultures that vex and disturb tyrants, torturing them day and night with perpetual terror and alarm. Envy, suspicion, fear, desire for revenge, and a thousand such conflicting disturbances wrench and frighten the soul out of the hinges of health. They wound and pierce it more grievously than cruel masters can torment their apprentices or servants with clubs, whips, chains and torture.”

We have many terrible examples of this kind, especially among the Turks: many jealous outrages. Selim killed Cornutus, his youngest brother, five of his nephews, Mustafa Pasha and various others. Bayezid, the second of that name among the Turkish rulers, jealous of Ahmed Pasha’s courage and greatness, had him killed. Suleiman the Magnificent murdered his own son Mustafa.

And it is common among them to kill their brothers, or any rivals, upon first coming to the throne: this is all the ceremony they observe at their fathers’ funerals.

What mad acts did Herod commit long ago in Judaea in his jealous fury, when he massacred all the one-year-old children? Or the emperor Valens in Constantinople, when he left no man of standing alive in his kingdom whose name began with Theo—Theodotus, Theognostus, Theodosius, Theodulus and so on? They all went to their eternal home because a diviner told him that a man of that name would succeed him in the empire.

And what furious schemes has Ivan Vasilievich, that Muscovite tyrant, carried out lately? It is astonishing to read of the extraordinary suspicion Suetonius reports in Claudius Caesar and Domitian: they feared every man they saw.

And Herodian reports the same of Antoninus and Geta, those two jealous brothers: one could not endure even the other’s servants, but killed him, his chief followers, and everyone attached to him or wishing him well.

Maximinus, perceiving that most men hated him because he had risen to such high honour from lowly beginnings, and suspecting that his humble parentage would be used against him, had all the nobly born senators killed in a fit of jealousy. He dismissed all the servants of Alexander, his predecessor, and killed many because they mourned their master’s death, suspecting them of treason because of their love for him.

When Alexander in his rage had caused his dear friend Cleitus to be killed, and now saw his subjects’ hearts estranged, says Curtius—no one dared speak to him—he began to fear for himself, lest they should attempt the same against him, “and said that they lived like so many wild beasts in a wilderness, afraid of one another.”

Our modern histories provide many notable examples. Henry III of France, jealous of Henry of Lorraine, Duke of Guise, had him murdered in his own chamber in 1588. Louis XI was so suspicious that he dared not trust his children; he suspected everyone around him of being a traitor. Commynes tells many strange stories of his behaviour.

How jealous was our Henry IV of King Richard II, for as long as Richard lived after his deposition? And of his own son Henry in his later days? The prince, clearly perceiving this, visited his sick father in a pale-blue velvet gown covered in eyelet holes with needles stuck in them, as an emblem of jealousy. By this means, and after speeches and assurances made for that purpose, he calmed his suspicious father.

Lifelong imprisonment, such as that of Robert, Duke of Normandy, in Henry I’s time; forbidding certain people to marry; and similar decrees and prohibitions are common in all states.

In a word, as he said, three things cause jealousy: a powerful position, a rich treasury, and a beautiful wife; or a doubtful title, much tyranny and many oppressive levies. In our country, being free from all these fears and miseries, we may be entirely secure and happy under the reign of our fortunate prince.

His good fortune has made him indebted to no one Except his people as a whole, And to them only for their love, Which they consider worthily bestowed. He is so firmly placed that he has no cause For jealousy or fear of disloyalty; The pedestal on which his greatness stands Is supported by all our hearts and all our hands.

But I wander, I admit. These different meanings of jealousy, and many similar things that torment human souls, are not what is properly meant here or included in our classification. We mean only the jealousy concerned with beauty and directed towards love, in which people can tolerate no rival or endure any sharing. This jealousy belongs to animals as well as human beings.

Some creatures, says Vives—swans, doves, cocks, bulls and so forth—are jealous just as human beings are, and equally disturbed by the fear of sharing their mates.

Young bulls fight for the whole herd; If they fear for their mates, Timid stags demand battle, And their bellowing reveals the fury they have conceived.

In Venus’s cause, what mighty battles Your raging bulls wage, what commotion for their herds! And stags and bucks, though so timid, Will fight and roar once they become jealous.

This is most clearly seen in bulls, horses and goats, especially bulls: “he admits no other to the pasture”; he will not allow another bull to feed in the same pasture, says Oppian. Stephen Báthory, the late king of Poland, used this as an emblem with the motto “A kingdom has no room for two.”