I study this stuff, after a fashion! (Historian of globalization and intellectual exchanges). I would conjecture that if something exists in multiple European l

I study this stuff, after a fashion! (Historian of globalization and intellectual exchanges). I would conjecture that if something exists in multiple European languages prior to, say, the 17th century (the advent of cheap mass market publications) it probably has a Greco-Roman or Biblical origin. Quite often you can narrow the guess to Horace or Virgil, since medieval and early modern writers apparently never got tired of quoting those two epigrammatically. Searching for "origin of armed to the teeth" yields a lot of just so stories about how it comes from the great age of piracy or is a reference to a Scottish armory but I doubt both given the fact that we know it was a thing in the 1550s Low Countries. I wouldn't be surprised if there was at least a medieval origin for it given that.