We can infer from the passage that Herodotus and Thucydides _____.

Oral history, accounts based on interviews with those who have taken part in historical events, is as old as the study of history itself. In the 5th century BC, the historians Herodotus and Thucydides, lacking the written sources on which modern historians have come to rely, questioned the survivors of the wars they described. In traditional societies without either a written language or widespread literacy, oral tradition passed down from generation to generation often serves as a substitute for written historical accounts.