The incident of Adam and Eve eating the forbidden fruit from the Tree of the Knowledge of Good and Evil has long fascinated readers of the Bible.
Many scholars in late antiquity and the early Middle Ages speculated concerning exactly what kind of fruit Adam and Eve ate.
An interesting seventh century Irish theological work entitled "The Odering of Nature" (De Ordine Creaturarum) proposed that Adam and Eve had eaten from a fig-tree.
“It is not at all clear from what species of tree Adam ate, but it is clear that immediately after sinning he covered his nakedness with the leaf of a fig tree (Gen. 3.7), the only tree Jesus cursed when he was in the flesh – not long before he accepted death on account of the fault of Adam. The tree immediately withered when he said: “henceforth no fruit will ever come from you” (Matt. 21.19), that is, it could no longer harm men as it had done before. For Christ gathered in that tree, that is, in the fig tree, the curse of the sin of Adam which infected the whole earth until he cleansed it with the drops of his own blood. For the Lord would have known for sure whether the first man received his guilt from this tree or from another.” (DOC X.13-14).