Saint Augustine based his definition of original sin on a misinterpretation of the Greek in Romans 5:12. According to Augustine’s misreading, sin is contracted and passed through the human race like a venereal disease. “We all were in that one man,” he wrote of Adam, who Augustine believed contained the nature of all future men, which was transmitted through Adam’s semen. The human race is therefore a “train of evil,” headed for destruction. The monk Pelagius argued against this concept, known as seminal headship.