Tatenen tꜣ-ṯnn

Most gods in this reference are lost because the evidence is thin. Tatenen is lost in a more interesting way: the Egyptians appear to have lost him too.

The source puts it about as bluntly as a scholar can:

He must have been one of the earliest gods of Lower Egypt, a personification of some power in nature — the exact attributes of which appear to have been unknown even to the Egyptians.

Sit with that for a second. A god old enough that the people worshipping him no longer knew what he was for. Not a god whose records were destroyed. A god who was still being named in hymns, still being written into compound titles, and whose original job had gone out of living memory while the name stayed in use.

Earth, plus stillness

The name breaks into two parts, and the second is the good one.

Ta is earth. That part is not in doubt.

Tenen is connected with a word meaning inertness, inactivity, rest, motionlessness — stillness, not as peace, but as not moving yet.

Put them together and you get something remarkable: not the earth as a body, not the earth as a place you stand on, but the stuff the world is made of, considered as dormant. Matter that is inert and is nonetheless alive.

Egypt already had a god of the earth as a body — Geb, who lies underneath the sky and whose laughter is earthquakes. Tatenen is doing something else. He is the substance itself, before it does anything.

That is a strange and rather modern thing for a religion to have a name for.

And the etymology might be a joke

Now the part that makes this honest.

The reading above comes from one hymn, and the passage it comes from is described as a very difficult one. And the scholar quoting it adds a warning that I think should travel with the idea permanently:

it is quite possible that in this passage the writer was not discussing the derivation of the name seriously, and was only making a play upon the words of similar sound.

So the single most quotable fact about this god — the god of inert but living matter — may be a nineteenth-century reading of an Egyptian pun.

I am not dropping it, because it might well be right and it is the only account anyone has. I am not asserting it either. Both the idea and the doubt belong on the page, and an idea this good is exactly the kind that gets repeated for a century without anyone rechecking the footnote.

Absorbed, and note which way round

What happened to him is clear even if what he was is not.

Early in the dynastic period, the priests of Memphis decided that Ptah — their local god, the craftsman, the one who makes things — could fittingly be identified with Tatenen. So Ptah's name was joined to the older god's, and the compound Ptah-Tanen entered the record.

Watch the direction. Ptah's name was joined to his. Tatenen was the senior party. The compound is not a merger of equals; it is a rising local god attaching himself to an ancient one, exactly as Amon later attached himself to Ra.

And then the usual thing happened. Ptah-Tanen took its place in the Memphite series beside Ptah-Seker and Ptah-Seker-Osiris, and Tatenen stopped having any independent existence at all. By the time the record gets thick, Tenen and Ta-tenen are simply names of Ptah.

What the hymn actually asks him to do

The difficult passage itself is worth reading, because whatever the etymology is doing, the image is unmistakable:

There was given to thee a Power upon the earth in its things which were in a state of inactivity, and thou didst gather them together.

That is a creation account with no speech in it and no craftsmanship. Nothing is spoken into being and nothing is built. The materials are already there, lying about, not doing anything — and the god's act is to collect them.

Whether or not the pun is a pun, somebody wrote a hymn in which the world begins with a god picking things up off the floor.