I do remember that in his great book,* Charles Freeman covered it in detail. Including the fact that a Bishop wrote Augustine a letter, telling him Original Sin was an insane idea. And not only un-Xian but inhuman, IIRC.
*The Closing of the Western Mind: The Rise of Faith and the Fall of Reason. An excellent read, and not to be mentioned in certain DU groups unless you want to experience Death By Google Nitpicking. "Wait, he said 436 years but it was actually 435 1/4 years. He obviously knows NOTHING!" Etc. etc. That's just an example I made up.
Now bend over and spread 'em, here comes a big hot load of Sophisticated Theology:
Augustine of Hippo (354430) taught that Adam's sin is transmitted by concupiscence, or "hurtful desire", resulting in humanity becoming a
massa damnata (mass of perdition, condemned crowd), with much enfeebled, though not destroyed, freedom of will.
When Adam sinned, human nature was thenceforth transformed. Adam and Eve, via sexual reproduction, recreated human nature. Their descendants now live in sin, in the form of concupiscence, a term Augustine used in a metaphysical, not a psychological sense. Augustine insisted that concupiscence was not a being but a bad quality, the privation of good or a wound.
He admitted that sexual concupiscence (libido) might have been present in the perfect human nature in paradise, and that only later it became disobedient to human will as a result of the first couple's disobedience to God's will in the original sin. In Augustine's view (termed "Realism"
, all of humanity was really present in Adam when he sinned, and therefore all have sinned. Original sin, according to Augustine, consists of the guilt of Adam which all humans inherit.
As sinners, humans are utterly depraved in nature, lack the freedom to do good, and cannot respond to the will of God without divine grace.
https://en.wikipedia.org/wiki/Original_sin
Everybody got that?