Oportet in primis qualis hominum quondam natura fuerit, quaeve illius passiones, perdiscere. Neque enim qualis nunc est, olim erat, sed longe diversa.
Principio tria hominum erant genera non solum quae nunc duo, mas & femina, verum etiam tertium quoddam aderat ex utrisque compositum. Cuius solum nobis restat nomen ipsum periit, Androgynum, quippe tunc erat, et specie et nomine, ex maris et feminae sexu commixtum...
Praeterea tota cuiusque hominis species erat rotunda, dorsum & latera circum habens, manus quatuor, totidemque, crura, vultus item duos tereti cervice connexos, et omnino consimiles. Caput utrique vultibus contra versis, unum...
Ob hanc vero causam tria genera et talia erant, quia masculum Sole genitum erat. Femina, Terra; promiscuum denique Luna. Utriusque enim luna est particeps.
Spherica vero erant et figura, et motu, quia parentum similia. Unde et robusto corpore et elato animo erant.
Quare cum diis pugnare tentabant, et in caelum ascendere quemadmodum de Ephialto & Oto scribit Homerus.
Iupiter igitur unaque dii ceteri quid agendum esset consultaverunt. Qua in re non parva inerat ambiguitas. Nam neque quomodo eos interficerent, reperiebat, ne eorum sicuti Gigantum, fulminando genus delerent: extincto enim hominum genere, humanus deorum cultus veneratioque periret, neque in tanta insolentia perseverare illos permittendum censebat.
Tandem sententiam Jupiter suam explicuit. Inveni, inquit, qua ratione fieri possit, ut & sint homines, & modestiores sint. Idque erit, si imbecilliores fiant. Unumquenque nunc duas in partes dividam. Ex quo et debiliores erunt, et nobis etiam magis id conducit. Numero siquidem plures erunt qui nos colent. Recti duobus cruribus ibunt. quod si rursus impie insurgere videantur, iterum in duo secabo, ut unico crure nixi, utpote claudi, saltare cogantur. Haec fatus bifariam partitus est singulos, instar eorum qui ova dividunt, ut sale condiant, vel qui capillis ova secant. Mandavitque Apollini, ut partitione statim facta, cuiusque vultum cervicisque dimidium in eam partem qua sectus est, verteret, ut scissionem sua considerans modestior fieret, reliquis autem mederit iussit. Ille continuo vultum vertit, et contrahens undique cutem in eum qui nunc venter vocatur, tanquam contracta marsupia et os unum faciens, medio in ventre ligavit.
Postquam natura hominum ita divisa fuit, cum quisque dimidium sui agnitum cuperet, inter se concurrebant, circumiactisque brachiis se invicem complectebantur, conflari unum affectantes...
--Aristophanes' Speech in Plato's Symposium (Symp.189ff; Translated from Greek into Latin by Marcilio Ficino 1592)
It’s especially important to learn about the early nature of man and what happened to them. For mankind did not used to be what it is now, but rather it was far different.
In the beginning, there were three types (genera) of people, not just the two we have now (male and female); there was also a third type, a mix of both. At this point in time, only its name (androgynous) remains, but then it was as the name implies, a mixture of male and female sexes.
Moreover, these humans were round in shape, having a spherical back and sides. They had four hands, the same number of legs, and two faces conjoined at the neck, and altogether symmetrical. They had one head, with both faces turned in opposite directions.
This is the reason there were three types (genera) of people, for the masculine type was born from the Sun, the feminine type was born from the Earth, and the third type was born from the moon, for the moon shares properties of both [i.e., the moon emits no light of its own, like the earth, but nevertheless it resembles the sun because is a heavenly body that shines].
Like their [heavenly] parents, they were spherical in both form and motion. For this reason, they had both strong bodies and powerful wills. In fact, they attempted to contend with the gods, and ascend the heavens the same way that Homer describes the feats of Ephialtes and Otis.
Therefore, Jupiter assembled the other gods together and deliberated on what to do. There was a great discussion on options: for he found that they could not kill humanity, as he had done with the Giants, for if the human race were destroyed, their worship of the gods would end. On the other hand, he reckoned that such insolence should not be allowed to go on unchecked.
Finally, Jupiter explained his plan. He said, “I have found a way that humans can remain, but yet become more modest. This will happen if they become weaker. I will divide each and every one of them in two. Then they will become weaker, and there will be twice as many to worship us. From now on, they will walk upright on two legs. But if they again seem to become arrogant, I will cut them in half again, and they will be forced to hop forward on one leg, like a crippled person.”
Having said this, he divided them in two, like those who cut eggs with a thread. And then he ordered Apollo to heal them and turn their faces and necks towards the part that was cut, so that upon looking at the wound they would become more modest. Apollo immediately turned their faces forward, and pulled together the skin in the middle of the stomach which now we call the navel.
From then on, the nature of mankind has been divided in such a way that when each one yearned to find their other half, they ran around each other, embracing one another and trying to fuse together again.