Dating of Abraham
Just when did Abraham live? We can't know that for sure either. It is difficult to find fixed events in Genesis that can be connected absolutely to dates established from archaeology.
One approach to dating Abraham is to backtrack from the first fixed event we find in the Bible -- a statement that Solomon laid the temple foundation in the 480th year after the exodus (1 Kings 6:1), which would date the exodus at about 1447-1446 BC. Working backward from the genealogies and other data in the Pentateuch puts the birth of Abraham in 2166 BC, and frames Abraham's life from 2166 to 1991 BC.[11] However, there are several problems with this approach. First, textual: the Greek Septuagint and the Samaritan Pentateuch agree with Paul (Galatians 3:17) that the 430 years of Exodus 12:40 apply to the whole time span between Abraham and the Exodus, not just the Israelite stay in Egypt as the Hebrew Masoretic text would suggest, bringing Abraham's birth year to 1952.[12] Second, genealogies in Bible occasionally skip generations.
Another approach to dating Abraham uses a combination of history and archaeology. One prong is the dating of the destruction of Sodom and Gomorrah (Genesis 19) by some kind of cataclysmic event, which archaeological evidence seems to point to around 1900 BC.[13]
You can also compare the lifestyle described in Genesis to archaeological findings to find a match. At the end of the Early Bronze Age (2400 to 2000 BC), Palestine was in a post-urban phase, with numerous settlements, camps, and cemeteries in the Jordan Valley and the Negev-Sinai. The Palestine described in Genesis also was sparsely populated, with few if any urban centers. By about 1800 BC, a number of urban centers had developed -- Dan, Hazor, Akko, Shechem, Aphek, Jerusalem, Jericho, and Ashdod. By 1600 BC, there were a number of heavily fortified sites, such as Gezer and Shechem. But, by 1550 BC, nearly every city in Palestine had been destroyed by the Egyptians driving out the Hyksos from Egypt.[14]
The Hyksos, a Semitic rather than Egyptian people, ruled over Syria, Palestine, and Egypt 1650 to 1542 BC until they were driven out by the Egyptian Amosis (Pharaoh Amenhotep I), founder of the Eighteenth Dynasty. It is easier to image the non-Egyptian slave Joseph rising to the position of second in the kingdom under a Hyksos ruler (1786 to 1575 BC), than under an Egyptian ruler, either before or after the Hyksos period. The period after the Hyksos dynasties would be expected to yield the pharaoh "who knew not Joseph" (Exodus 1:8), who would oppress the Semitic peoples remaining in Egypt.[15]
Depending upon how one views the evidence, Abraham might fit into Middle Bronze I (2100-1900 BC, Nelson Glueck and William F. Albright), Middle Bronze II (1900-1550, Ephraim A. Speiser), or the Amarna Period of the Late Bronze Age (early 14th century, Cyrus H. Gordon).[16] Of course, there are no archaeological findings that refer specifically to Abraham, Isaac, and Jacob, so where they fit into the archaeological periods isn't precise, but we can place the birth of Abraham with some degree of confidence between 2100 and 1800 BC.[17]
Nibley has a small section on dating, and he states that the times are argued roughly along the same lines as the article above. Cutting and pasting the above was easier than typing out the chapter from "Abraham in Egypt".
Source:
http://www.jesuswalk.com/abraham/0_intro.htm