LoL
I just came up with maybe because tanks were first deployed to the "cavalry" units? ... or .. whatever, but if that is the case, Matilda was not with a "C" ...
But if it is about medium tanks, .. actually what is the line for medium and heavy today? I only notice these days, tanks become "light tanks" or MBTs (main battle tanks) .... maybe heavy tanks become a historical name for WWII only? ....