The problem with anything historical is that it can never be 100% accurate, people interprate things in theyre own way, taking into account languages have changed which only adds to the confusion of records.

when there are even doubts surrounding the jews being gased in ww2 which was less then 100 years ago how can you be sure about something that happend over 2000 years.

how do you think the world would react if it was found a clear blood line?
Are the stories in the bible better off in the past as todays world just couldn't handle
those sorts of things?