Methuselah
What is one of the biggest arguments "against" the historicity of biblical characters? Well of course, it is their unbelievable longevity.
Take Methuselah as an example, he is said to be the bibles longest living human at an incredible and unbelievable 969 years.
Methuselah (US: /məˈθuːzˌlɑː/) (Hebrew: מְתוּשֶׁלַח Məṯūšélaḥ, in pausa מְתוּשָׁלַח Məṯūšā́laḥ, "Man of the javelin" or "Death of Sword";[1] Greek: Μαθουσάλας Mathousalas)[2] was a biblical patriarch and a figure in Judaism, Christianity, and Islam. Having died at the age of 969, he lived the longest of all human figures mentioned in the Bible.[3]
Enmebaragesi
However, we have a king on the Sumerian king list named Enmebaragesi whom is credited with having reigned in Sumeria for 900 years and until recently was thought to be a mythological figure. However recent archaeological excavations have found Enmebaragesi a place in the history books afterall.
Enmebaragesi (Sumerian:𒂗𒈨𒁈𒄄𒋛)[3] originally Mebarasi (Sumerian:𒈨𒁈𒋛)[1] was the penultimate king of the first dynasty of Kish and is recorded as having reigned 900 years in the Sumerian King List. Like his son and successor Aga he reigned during a period when Kish had hegemony over Sumer.a[4] Enmebaragesi signals a momentous documentary leap from mytho-history to history, since he is the earliest ruler on the king list whose name is attested directly from archaeology.
Cattle count
Now even though Enmebaragesi is now believed to have historicity, we still have the problem of this 900 year reign. Obviously we do not believe he reigned for 900 years.
My initial theory was that the 900 years represented tax years, and not calendar years, as the ancients used to operate a tax system called the cattle count which did not operate around the current annual year system. However I have kind of ditched this theory, because for Enmebaragesi to have reigned for a total of 900 cattle counts would have meant his administration was a very greedy administration indeed, and his people must have been extremely poor having to keep up with all those cattle counts.
In ancient Egypt, the cattle count was one of the two main means of evaluating the amount of taxes to be levied, the other one being the height of the annual inundation. A very important economic event, the cattle count was controlled by high officials, and was connected to several cultic feasts. In addition it served as a means of dating other events, with the entire year when it occurred being called "year of the Xth cattle count under the person of the king Y". The frequency of cattle counts varied through the history of ancient Egypt; in the Old Kingdom it was most likely biennial, i.e. occurring every two years, and became more frequent subsequently.
Ziusudra
A better explanation might come from Ziusudra, whom is a Sumerian king that is also being thought of as less and less mythological and more and more historical with archaeological excavation. Apparently Ziusudra is credited with a reign of 3,600 years. It has been suggested though, that this is a copyist error with 10 sars being (which equals 3,600 years) mistakenly used instead of 10 years. Therefore archaeologists would be of the belief that Ziusudra reigned for 10 years, not 10 sars.
He is recorded as having reigned as both king and gudug priest for ten sars (periods of 3,600 years),[3] although this figure is probably a copyist error for ten years.[4]
Conclusion
So do we now have to review the actual ages of those mythological and biblical figures? They may not be that old afterall.