Irenaeus (130-202 AD) pre-dated Augustine of Hippo by 150 years. Irenaeus introduced the doctrine of original sin before Augustine, although the term "original sin" would be developed later. Two quotes from Irenaeus from his compilation, "Against Heresies."
"In the first Adam we offended God, not fulfilling His commandment...to Him alone we are debtors, whose ordinance we transgressed in the beginning." Against Heresies 5, 16, 3.
"In Adam disobedient man was stricken."
Ibid. 5, 34, 2.
The point? Original sin was not an Augustinian invention. It existed in the early patristic age.
"In the first Adam we offended God, not fulfilling His commandment...to Him alone we are debtors, whose ordinance we transgressed in the beginning." Against Heresies 5, 16, 3.
"In Adam disobedient man was stricken."
Ibid. 5, 34, 2.
The point? Original sin was not an Augustinian invention. It existed in the early patristic age.