almost as long (if not longer) then recorded history
Upper Egypt and Lower Egypt
The earliest known sundials existed in ancient Egypt. The earliest description of a sundial is from the Old Testament of the Bible.
Ever since it existed
neither, Egypt refers to a nation-state which existed after the neolithic communities of the region. Early Egyptians may have used neolithic stone technology but the Empire of Egypt also existed during the bronze and iron ages.
Preistesses, royal officials, administrators, and artisins.
It was Egypt's lifebloood without it Egypt would not have existed. The needed the Nile for farming, drinking water bathing, doing laundry you name it.
the old capital of egypt
First of all, Egypt is not a city at all. It is a country. Second, it existed from about 6000 B.C. to 30 B.C.
It was never lost. People have known about it since it first existed.
Memphis was the capital of old kingdom Egypt.
Egyptian civiliation has been around for millenia... there are a LOT of "old days" in the history of that country, and a lot of changes within the millenia in which Egyptian civilization existed. You would need to be a bt more specific about which "old days" you refer to.
Ancient Egypt probably would not have existed due to no water sources to drink and farm with.