Prehistoric archeology is concerned with the period in human history before written records. In the Nation's Capital, this is usually considered the time before 1600 AD. To piece together the past, prehistoric archeology relies on carefully developed cultural chronologies - the study of change in artifacts over time. Archeologically recovered plant and animal remains provide valuable knowledge about the foods consumed by prehistoric peoples. The arrangement of houses within sites and of sites over the landscape can tell us something about the way prehistoric peoples used the land and organized themselves, socially and politically. Though they have no written records to assist them, prehistoric archeologists sometimes use information from the descriptive studies of non-Western peoples to interpret events in prehistory.