John Downs, the president of the Italy and Colonies Study Circle, has been a philatelist and a postal historian for a very long time, originally collecting British Commonwealth but turning to mediaeval Papal States postal history for the last couple of decades.  Being a Latin scholar serves him well in this regard and he has used these skills to assist with the Corsini correspondence some years back.  He is also an expert in micro philately and has worked for the British Postal Museum among others.