In ancient Egypt, the primary evidence for the Predynastic Period, principally the fourth millennium BCE, derives from burials. In Upper Egypt, there is a clear trend over the period towards greater investment in mortuary facilities and rituals, experimentation in body treatments, and increasing disparity in burial form and content between a small number of elite and a larger non-elite population. In Maadi/Buto contexts in Lower Egypt, pit burials remained simple with minimal differentiation and less of a focus upon display-orientated rituals.