Wikipedia says that the story of Abraham is fictional, an ex-post construction:
The Abraham story cannot be definitively related to any specific time, and it is widely agreed that the patriarchal age, along with the exodus and the period of the judges, is a late literary construct that does not relate to any period in actual history. A common hypothesis among scholars is that it was composed in the early Persian period (late 6th century BCE) as a result of tensions between Jewish landowners who had stayed in Judah during the Babylonian captivity and traced their right to the land through their "father Abraham"
but I recently read that Abraham time is about 1980 B.C.
Does anyone happen to know how this speculation was derived and what currency it has?