Ancient Egyptian royal ideology held that a deceased king continued a genuine existence in the afterlife and, further, that his ka, the vital force sustaining that existence, required ongoing material offerings of food, drink and incense exactly as a living person requires sustenance, a belief that made a mortuary temple not a memorial in the modern commemorative sense but a functioning religious institution whose purpose was to keep a dead king actually fed and actually honoured indefinitely.
Every major royal tomb of substance, from the pyramid complexes of the Old Kingdom through the rock cut tombs of the New Kingdom Valley of the Kings, was paired with a dedicated mortuary temple, and these temples were endowed with agricultural estates, staffed with priests, and provisioned on a continuing basis specifically to fund the offerings the cult required, an economic as well as religious commitment that could represent a substantial and permanent claim on the kingdom's resources long after the king himself was gone. Priests serving individual royal mortuary cults were commonly organised into phyles, rotating groups who served in shifts across the year rather than maintaining constant year round presence, a practical staffing arrangement attested for major cult institutions more broadly across Egyptian temple administration.