Ares day and Ertag ... Greek and Germanic

Hi all, I'm still struggling with the etymology of the Bavarian names
for Teusday (Ertag, Erichtag, Irtag, etc) and am hoping someone can
shed some light on the issue.

The following is taken from Jacob Grimm's Teutonic Mythology, chapter
9. Notes in [[ ... ]] are taken from Grimm's footnotes or Supplement
section.

<begin quoted section>

Still more plainly are High German races, especially the Bavarian
(Marcomannic) pointed to by that singular name for the third day of
the week, Ertag, Iertag, Iertag, Irtag, Eritag, Erchtag, Erichtag,
which answers to the rune Eor.

True, the compound Ertac lacks the genetive ending -s which is
preserved in Ziestac, and I have not been so fortunate as to hunt up
an Erestac (In a passage from Keisersberg quoted by Schm. 1, 97, it
is spelt Eristag, apparently to favour the derivation from 'dies
aeris.') in the older records of the 13-14 centuries; nevertheless
the coincidence of the double names for the day and for the rune
should be conclusive here, and we must suppose an OHG. Erestac, to
match the Eresberg.


((Grimm compares Zio to Zeus and then states:))
we see at a glance that Eor, Er, Ear, is one with Arhj the son of
Zeus;



Have we any means now left of getting at the sense of this obscure
root Eor?
The description of the rune in the AS. poem gives only a slight hint,
it runs thus:

Eor is horrible to every knight,
when the corpse quickly begins to cool
and is laid in the bosom of the dark earth.
Prosperity declines, happiness passes away
and covenants are broken.

or

Earth is loathsome to each nobleman,
when flesh firmly tries to choose the ground,
fallen fruits as bedmates,
joy vanishes,
man turns traitor.
((Rune poem translations not from Grimm)

The description is of death coming on, and earthly joys dropping off;
but who can that be, that at such a time is burdensome (egle, ail-
some) to men? The ordinary meaning of ear, spica, arista, can be of
no use here; I suppose that approaching dissolution, a personified
death is to be understood, from which a transition to the destructive
god of battles, the brotoluigÒj, miaifÒnoj Arhj , is easy to
conceive. [[ Or, without the need of any transition, Ear might at
once be Ares: 'war is burdensome in old age'.]]

Arhj itself is used abstractly by the Greeks for destruction, murder,
pestilence, just as our Wuotan is for furor and belli impetus.

<end quoted section>


To follow up, I copied the next bit from the Gothic Language list:

<start section>

several weekdays names were borrowed by the Goths from the Greek in a
manner like this:

ARHOS hHMERA "the day of Ares" > *Arjaus dags or *Areins dags > OB
erintag > NB ertag, erchtag, ergetag, irtag, irchtag

PEMPTH hHMERA "the fifth day" (> via a colloquial compound
*PENTHMERA - ?) > *paintedags > still more "Gothicized" *pintadags >
NB pfinztag, pfünztag

PARASKEUH "(the day of) preparation" > paraskaiwe (Mc 15:42) >
*pareinsdags > OB pferintag

SABBATOU hHMERA "the day of Sabbath" > sabbato dags (Mc 2:27 et
passim) > *sambatadags > OB sambaztag > NHG Samstag

<end section>

Does the progression of ARHOS hHMERA > *Arjaus dags or *Areins dags >
OB erintag > NB ertag, erchtag, ergetag, irtag, irchtag ...
seem valid to you all?
Do these Bavarian names derive from Ares??

Thanks in advance!
-Aydan