The physician Hippocrates had a touch of this disease. When he was to travel from home as far as Abdera and other distant Greek cities, he wrote to his friend Dionysius—if those letters really are his—to watch over his wife in his absence, as Apollo set a raven to watch his Coronis, although she lived in his house with her parents, whom he knew would look after her.

Yet this would not satisfy his jealousy. He wanted his close friend Dionysius to live in his house with her throughout his travels and “observe her behaviour, how she conducted herself in her husband’s absence, and see that she did not desire other men.”

“For a woman needs a supervisor to keep her chaste. They are all bad and sexually unrestrained by nature; unless curbed in time, like an unpruned tree they will become full of wild branches and suddenly degenerate.”

Especially in their husbands’ absence: though one Lucretia and one Penelope were faithful, Clytemnestra made Agamemnon a cuckold, and undoubtedly too many women are like her. If their husbands stay away too long on unnecessary business, they have good reason to suspect them; or if the men run off one way, their wives at home will stray another: “one thing in return for another.”

Or if they are present but do not give them the satisfaction they should: “Nights spent asleep are first unwelcome, then detested.” They cannot endure sleeping alone or abstaining for long.

Peter Godefridus, in book 2, chapter 6 of his work on love, has a story from the life of St Anthony about a gentleman who, on that good man’s advice, would not have intercourse with his wife during Passion Week; but for his pains she put a pair of horns on his head.

He has another such story from Abstemius. Someone persuaded a newly married man to abstain for the first three nights, promising that he would then prosper in livestock for the rest of his life. But his impatient wife would not wait so long: he might do well with his cattle, but not with his children.

Heinsius tells a similar story about an impotent, listless scholar, wholly absorbed in his studies, who was a friend of his. Happening to see a beautiful girl singing and dancing, he insisted on marrying her. The match was soon made, for he was young and rich, “handsome in the face, smooth in body, skilled in many arts and wealthy in fortune,” like Apollo in Apuleius.

On the first night, having drunk freely, as people in that country do, my fine scholar was so befuddled that he fell fast asleep as soon as he was put to bed and never woke until morning. Then, greatly embarrassed, “when lovely Dawn blushed with purple roses”—when the fair morning began to shine with a purple hue—he made some excuse, I know not what, from Hippocrates of Cos and so forth, and for that occasion it passed muster.

But when he afterwards failed to perform as a man should, she took up with a lively fellow. While he sat up late at his textual criticism, correcting difficult passages in Festus or Pollux, then came cold to bed and kept telling her what he had accomplished, she paid little attention to what he said, and so on.

“She would much rather have had another passage put right, which he did not recognize as corrupt.” So he stayed late at his studies, and she at her pleasures—“for elsewhere the merry fellow was spending his nights”—hating all scholars because of him. At last he began to suspect something and turned a little yellow, as well he might: it was his own fault.

If men become jealous in such cases, as often happens, the remedy is in their own hands: they have only themselves to thank. Who will pity them, says Neander, or be very angry with such wives, “if, having first been deceived, they deceive their husbands and make them cuckolds”—if they deceive those who cheated them first?

A lawyer’s wife in Aristaenetus threatened to make him a cuckold because he neglected his business “when attention should be given to bed.” She did not hesitate to tell Philinna, one of her women friends, as much—and loudly enough for him to hear: “If he pursues other men’s affairs and leaves his own unattended, I shall have an advocate to plead my case. I do not care whether he knows it.”

A fourth major cause of jealousy may be this: when a man who is misshapen and, as Pindar says of Vulcan, “born without the Graces,” shaggy and rough, though virtuous in character, marries some beautiful, fastidious creature or flighty woman, he begins to suspect, as well he may, that she does not love him.

“Chastity has a great quarrel with beauty”: beauty and chastity have always been at odds. Abraham was jealous over his wife because she was beautiful; so was Vulcan over his Venus when, as Philostratus says, he made her creaking shoes “to prevent her committing adultery, the sandal informing against her”—so that he could hear whenever she moved. Mars “took offence at this”: he was not at all pleased.

Vulcan had good reason to act as he did, for she was none too chaste. Your pretty faces commonly have this fault, and it is hard to find, says Francesco Filelfo in a letter to his friend Saxola, an honest rich man or a handsome woman who is neither proud nor unchaste. “Can she be beautiful and chaste as well?”

For often a serpent has hidden itself beneath bright grass; Under the appearance of beauty, to an unwary husband A wicked soul often sells itself.

A man who marries a wife for her facial beauty alone should expect, says Barbaro, no better success than Vulcan had with Venus or Claudius with Messalina.

In such cases it is almost impossible for the wife to restrain herself or for her husband not to be jealous. When he is so deficient, weak, ill-proportioned and unattractive in the qualities women most desire, while she, on the other hand, is perfectly beautiful and vigorous, how can she love him unless she is exceptionally virtuous?

Even if she is not beautiful, if he admires her and thinks she is, she is perfect in his imagination. He believes it impossible for any man alive not to dote on her as he does—to look at her without lusting or coveting, or to be in her company without laying siege to her chastity.