Plato Symposium 189c

In the first place, let me treat of the nature of man and what has happened to it; for the original human nature was not like the present, but different. The sexes were not two as they are now, but originally three in number; there was man, woman, and the union of the two, having a name corresponding to this double nature, which had once a real existence, but is now lost, and the word "Androgynous" is only preserved as a term of reproach. In the second place, the primeval man was round, his back and sides forming a circle; and he had four hands and four feet, one head with two faces, looking opposite ways, set on a round neck and precisely alike; also four ears, two privy members, and the remainder to correspond.

Date: 385-370 B.C.E.
* Dates are based on scholarly estimates

Genesis Rabbah 8:1


... R. Jeremiah b. Leazar said: When the Holy One, blessed be He, created Adam, He created him as androgynous for it is said, Male and female created He them and called their name Adam (Gen. V, 2). R. Samuel b. Nahman said: When the Lord created Adam He created him double-faced, then He split him and made him of two backs, one back on this side and one back on the other side. To this it is objected: But it is written, And He took one of his ribs, etc. (Gen. 1, 21) [Mi-zalothaw means] one of his sides, replied he, as you read, And for the second side (zela‘) of the tabernacle, etc. (Ex. XXVI, 20)....

Date: 500 C.E.
* Dates are based on scholarly estimates