I took up your offer and did a quick check on "google" as to the burning of the Somerville convent. I had never heard or read about it. Apparently it was attacked and burned in 1834, but there is no reference to the several hundred nuns who you believe were were killed in the assault. Is there another reference that I can consult? It seems strange that they include an article, but omit the deaths of so many people.
Please note that in post #79, I retracted my assertion as I may have leapt to some undefensible conclusions.