Do not know for sure but it may mean:
V = Ventito - I come often
S = Saluto - To Pay Respect
LL = Laetificus Letificus - And Spread Happiness
M = Maxime - to the highest degree
Just my guess!
OMG. So text messaging abbreviations were around way back in 40 AD!IMHO, there really is nothing new under the sun!
LOL!
If you have to chisel the message in stone you would use short cuts too.
Our ancestors (despite what some believe) were not stupid.
Could be as SPQR means:
The Senate and People of Rome
Nothing is new.