People are seeing Elvis, even today
History is supposed to be a reality recorded. We can surely have a direct experience of reality. Not the past events before our time. So
we have to believe. Like, you may not have a direct experience of your grandfather, but your father does. Dharmic religions say that there are two paths of knowledge: ascending and descending. Ascending is by our own efforts, we can investigate about the past, like archaeology etc. Descending is accepting knowledge from someone who has it. Like, your father has the knowledge of his father, so you can learn about your grandfather. Secular aspect of that is what we call authority. We learn from authority, and that is of such a dramatic importance, that I call it an instinct - we are programmed to accept authority. As babies we are helpless to survive and our only chance is to learn from those who were already successful in survival. Later, in adolescence, we rebel against the authority, in order to become one ourselves. Religious aspect of descending knowledge is called dogma. Originally it means a truth revealed by God, and that is very different from a pejorative meaning of dogma we have today (but which is sadly well deserved).