(Not sure if this should be on the English.SE. I ask here since it is quoted from a historical document.)
Sir,
I do by these summon you to deliver up the City of Oxford into my hands, for the use of the Parliament. I very much desire the preservation of that place (so famous for learning), from ruin, which inevitably is like to fall upon it, except you concur. You may have honourable terms for yourself and all within that garrison if you reasonably accept thereof. I desire the answer this day, and remain
Your servant
THO: FAIRAX.
(FAIRAX appears to be a typo for Fairfax, a commander in the English Civil War)
What does THO stand for? Usually I would expect a Google search to easily find the answer, but THO appears to be a rather rare acronym, and none of them seem appropriate. The most "sensible" appears to be "The Holy Observer", which nonetheless sounds like nonsense.