For example, Craffert writes:
What historians learned from anthropologists is that "people lead meaningful lives, and that these meanings can only be discovered within the context of those lives, it cannot be imputed to them on the basis of some previously established ideas about the biological or psychological makeup of people" (Cohn 1980, 201). Therefore, anthropological historians recognise that they "must grasp the absolute presuppositions, the unspoken assumptions, of the society under review, in order to understand what has occurred" (Stanford 1986, 93). (Craffert 2005:611)
In other words, it will not do to run through historical documents (the Gospel of Mark, the Acts of the Apostles, Xenophon's Anabasis, or whatever) and attempt to isolate historically credible or plausible data that the historian can then use to reconstruct the past. Our documents are situated accounts of the past, written by people with particular perspectives—biases, expectations, values, ideas about what could happen, what should happen, and so on. And unless historians can approximate to some significant degree those particular perspectives, we simply will not be able to get in touch with "what actually happened" (the ultimate goal of most historiography) in any meaningful sense.
As a result, "[a]nthropological historians approach the documents as narrative constructs themselves of cultural realities and experiences" (Craffert 2005:611). This way of approaching texts matters, I think, not just because this more accurately perceives what our historical sources are (though this is true). Instead, it helps us to appreciate more acutely that our own historical reconstructions are similar phenomena: expressions of the past in terms that make sense within, communicate meaningfully to, and provide orientation for people in the present. Back in 2005 I made a similar point in a post on the SBL Forum (available here).
As I said above, I'm not persuaded by Craffert's main thesis regarding the claim of Davidic descent in the Gospels and (I would argue) during the life of the historical (= real) Jesus. However, he has offered us real insight in how we engage historical practice—historiography—as we try to know with some degree of precision and/or certainty what the past actually was. I strongly recommend you check out this essay.