A propos the Diocletian quote, I support Max Kelly and John Isbell : I do not like to jump in with both feet without seeing the locus and its context, but I would say that the sense is "Surveying is generally acknowledged to be a social benefit but astrology is everywhere taken to be pernicious" "Geometria" at this time would have military overtones - design of fortifications, disposal of forces over terrain etc. "Mathematicus" almost certainly means "astrologer" or "soothsayer". Astrology was not respectable, being seen as a vulgar oriental import. Two centuries earlier, Juvenal in his sixth satire (line 562) says "Nemo mathematicus genium indemnatus habebit" (No astrologer gets a reputation until he is convicted) a line which the Diocletian quote could well be referring back to. Sorry if this is a disappointment - but a nice quote anyhow! -- Gavin Wraith ++++++++++++++++++++++++++++++++++++++