pete... no one SHOULD claim that Ussher was a 'crank'. He was sincere, talented (for the 1600s)....but simply wrong in his premises about how things worked. In those days, belief in the literal truth of the Bible was pretty common, and Ussher's 'work' simply put numbers to common beliefs. But even then, he had to make many assumptions when scriptural details were lacking and had no idea to what extent translations and 'editions' of the Bible had affected what he had to do in calculations.... much less any idea how science would centuries later show that geology and chemistry and paleontology had to be given attention.

The message in the Bible had to be considered apart from the historical disputes.