Human phenomena always acquire their significance in historical contexts; thus history is a source of meaning for phenomenological inquiry.
Sometimes we may gain unique insights into human phenomena when we study those phenomena in histrorical contexts. Through history we may learn that a particular phenomenon has undergone certain changes in meaning. For example, it is quite likely that our felt experience of social rules may have changed over the last few hundred years. Rules have consequences for the way we see ourselves. A slight sharpening of certain rules will make one realize that one acts differently from the way one really is. We may like to dress in a certain way but the social rules do not allow it. In public we behave differently from the way we behave in the privacy of our home. This is also the context for the possibility of the emerging consciousness of the meaning of public and private spheres. And, phenomenologically speaking, the history of the separation between the private and the public can be taken as a heuristic metaphor for the emergence and development of inwardness and the experience of an inner life. These processes likely reach far back into human history.