I have been studying the life of Emperor Constantine, his conversion,
and his subsequent rule.  One area that is particularly interesting to
me is the faith of his father, Constantius, and his mother, Helena.

The reason this came up is actually due to a discussion within my
fraternity (of which Constantine is an inspiration) regarding whether
Constantine's conversion was truly genuine or if it was simply an act of
practical politics.  We ended up discussing the possibility of the
faith of his parents, which would, in my opinion, affect the nature of his 
conversion.  I have heard that Helena was in fact a Christian and that
Constantius, though a pagan, did in fact believe in something called
'Sol Invictus' which would imply monotheism.  What were the faiths of
Helena and Constantius?

I've tried searching for an answer, but I didn't really find what I'm
looking for.  I would like to see if there are any online resources or
websites that treat this question in any kind of meaningful way. I'm
always willing to tip for an answer that surprises me or brings up
something I had not considered, as well (if you look at my question
history)

Personally, I tend to believe that the border between paganism and
Christianity was extremely fuzzy in the late 3rd and early 4th
century; too fuzzy to really say what Constantius Chlorus and Helena
believed in. I don't have the printed sources ready I used for other
purposes some time ago, but I remember some interesting details:
- It was not uncommon that Roman citizens of Christian belief
nevertheless held symbolic positions as pagan priests connected with
their position in a municipality or their office.
- Even in the 5th century, Christian Roman Emperors were still
officially proclaimed gods by the Senate as part of their
inauguration. No one, not even the Church, obviously found it
problematic that the head of a Christian state had "deus" in the list
of his titles.
- The idea of clearly separating religions from each other was still
new, even for Christians. The Romans, as all peoples of the
Hellenistic world, had no problem worshipping dieties from other
religions than the one they usually practised. One could be a follower
of some imported oriental diety and simultaneously worship the Olympic
gods, and hardly anyone found this remarkable. Constantine the Great,
for example, paid respect to the Christian god (though he was baptized
only shortly before his death, if at all), but also to the official
Roman gods and to Sol Invictus. He held the office of the Chief Priest
and had praises and thanks to the pagan gods included on the monuments
erected upon his order. All this without remorse, as I could imagine.

Maybe Flavius Valerius Constantius Chlorus went to church from time to
time, listened to what the Christian priests had to say and found it
interesting and evident. That could explain why he did not carry out
anti-Christian orders. But being a Roman, he just added his occasional
tribute to the new god to his repertoire of dieties. At least, I could
imagine this.

Regarding Constantine's mother Helena: Whether she was Christian or
not at the time Constantine grew up is almost impossible to determine.
Some argue that the fact that Constantius Chlorus did not marry her
(which is not totally clear), though their relationship was enduring,
would be proof for her Christian belief - an aspiring officer would
not have ruined his career by marrying a Christian woman, while
keeping her as a concubine was acceptable. However, there were also
other reasons for not marrying Helena. Important persons married for
important reasons only, for political or financial gain, but not for
love. Constantius Chlorus (and surely Helena, too) knew that for his
future ambitions it was better to not marry a low-class woman, in
order to stay an interesting potential groom for a woman form an
influential family. He could always marry such a woman and keep Helena
as his "real" partner (and his wife would most likely do something
similar). So the relationship between Constantine's father and mother
does not prove anything.

Just my thoughts...

Scriptor

Those are all very good points scriptor, and now I'm tempted to cancel
my question :)

I remember learning at some point that Romans would often adopt
regional deities without any problems for their own religions but I
had forgotten that point.  Thanks for your comments.

Friends,

Scriptor's comment make sense. In the interests of accuracy, however,
let me add that Constantine was baptised on his deathbed, only, so to
discuss his "conversion and subesquent rule" might lead in the wrong
direction.

As an aside, with regard to "Sol Invictus", the worship of which was a
serious competitor to Christianity at the time (and monotheistic, as
you point out), Constantine's interest in this cult led to some
confusion in his mind which, in turn, contributed to the selection of
SUNday as the day of rest among Christians. Not the only reason but I
take satisfaction in noting that one of our most enduring insitutions
is - at least partly - based on a misunderstanding.