We found this marking on some plaster in a 4th century paleo Christian catacomb under a lesser known Basillica in Rome. Anyone know what it is or what it represents? It's not like the usual Alpha and Omega symbols.

Probably a high voltage electrical conduit behind it
Papal insignia at a guess from my metal detecting days?
Papal insignia at a guess from my metal detecting days?
Despite my earlier smart arse answer, this was my first thought, it's a bit like the Papal crossed keys
'No choirboys kept in here overnight'.
It's either this

or this

Your question falls in my field of academic expertise, and I’ve never seen such a symbol in relation to Christianity before. I will make enquiries.
Thanks all (but electrics were seriously lacking down there). For context, this was opposite. 
Just checked with an academic colleague who is senior to me in the field, and he didn’t recognise it either.
Weird.
I’ll keep looking.
There are some close ones on here from that era but not the same!
Scroll down to look at the diagrams op.
https://quadriformisratio.wordpress.com/2013/07/01/the-sign-of-the-cross/
Enhanced it a little on my mobile.
That design is echoed on your second pic I think op?
From your second pic.
Some old masonic symbols are similar and might have been inspired by ancient iconography perhaps?
I'm stumped but it's been interesting looking!
I've asked someone on Twitter about it, so that'll end well. 😁
Had a quick shufti at the article poopscoop posted, and these have a certain resemblance, so there may be an early Christian connection…

Up the Hammers!
Wonder if it's a combination of a cross formed of four circles along with the crossed bones you sometimes see in much older graveyards. It does look a bit familiar though but maybe its what poopscoop said and it looks similar to an old masonic symbol
Next thread: can someone come up with an STW symbol that we can all get tattooed beneath our beards or scratch somewhere
Next thread: can someone come up with an STW symbol that we can all get tattooed beneath our beards or scratch somewhere
See @mark 's shoulder
There's an active STW thread about this... something about a disproportionate cross, from memory?
Tag.
Seriously, I have seem something like this on a Danish megalith.
Off to find some pix.
Also, it might be worth asking on the modernantiquarian website.
franciscobegbie
Free Member
Is this how the apocalypse starts? An ancient evil unleashed into the physical world via an otherwise innocent post on a bicycling forum?
It could be but evil is more likely to use one of the political threads as a portal into this universe I reckon.lol
Don't suppose you have a picture of the symbol taken from slightly further away? There is some detail at the end of the cross that are clipped off.
Also it would be nice to see the symbol in the wider context of the wall? Is it part of a larger picture/design?
You absolutely have to interrupt your holiday to answer this by the way. You can't leave us hanging. 😁
We found this marking on some plaster
Can you carefully ease the piece of plaster off the wall and bring it back?
Lord Elgin would approve.
It would help to know which Basilica it is. @saxonrider is obviously the expert here, but I think there was quite a bit of variation of Christian symbology in the 4th C - It wasn't settled, although you'd expect to see a variation of the Chi-Rho or Ichthys presumably.
A saint's cross?
Thanks again everyone. Back in the UK now 😞 and so only my work being interrupted. I'll see if my kids took any better photos. The reason we found that symbol interesting is because we thought we recognised it but couldn't place from where. I'm starting to think it might just be the logo of a local big wig? Having had time to do a little reading.. The church is prob. 4th century, the sarcophagus 2nd C, the altar 6th C but the paintings 8th C and so not as old as I first thought. There is also a fair bit of info about it on the web... It's getting less and less Dan Brown. For those still interested it is under La Basilica Sotterranea Di San Crisogono in Trastevere.
And because this is more interesting than work I think I could be convinced that it is just the monogram of Pope Gregory III?
Is this how the apocalypse starts? An ancient evil unleashed into the physical world via an otherwise innocent post on a bicycling forum?<br /><br />
Usually only if the individual is Chaotic Evil. I’m Chaotic Neutral, so wouldn’t be messing with that sort of stuff! 😁
Is this how the apocalypse starts? An ancient evil unleashed into the physical world via an otherwise innocent post on a bicycling forum?
Usually only if the individual is Chaotic Evil. I’m Chaotic Neutral, so wouldn’t be messing with that sort of stuff! 😁
I've long held the notion that it will be the mathematicians who will bring about the ending of the universe.
They'll stumble upon the formula that the entire thing is run on, and one day they'll innocently jot it down on a blackboard, and as the piece of chalk scribes the last part, when it leaves the board, the universe will begin to unravel at that point, eventually consuming everything.