The first domain name

[snopes]

Comment: symbolics.com is claiming to be the first domain name ever
registered (on March 15 1985), and that knowledge is being passed around
as fact via factoid emails. Since the Internet started as an ARPA
project, open only to government, military, and educational institutions,
I thought that was odd.

The Wiki for symbolics states that it is the first *.com* domain ever
registered, which I more readily believe.

The solution gave me 2 questions for Snopes:

Is symbolics.com really the first dot com?

and

What was REALLY the first domain name (any TLD) ever registered?

My guess on the latter question would be pentagon.mil or something
governmental, but since DNS came after the Internet, maybe it would be
usc.edu since Jon Postel wrote the RFC for DNS (RFC882), and that's where
he was at the time.

The RFC uses an example of f.isi.arpa, but I don't know if that's real or
not. Also, the RFC looks at DDN and CSNET as TLDs - also possibly
theoretical.

A similar question I would think would be: what was the first root nameserver, and when was it decided (at large) that the world wide distribution of host names to computer identifiers (I suppose by then IPs) via hosts files should finally be replaced by the domain name system? Did the root nameserver have a name for itself?

Or are you asking about the first hostname itself, which wouldn't have anything to do with DNS, as naming was first handled manually by aforementioned host files?