This. But even what the article agrees with is wrong: "It only works if you focus solely on western Europe, where the decline of Rome left a nasty gap in the records." -- There is not really a gap. We have fewer records, but still covering a lot. They may not be autographs, but that is not very different from the situation with antiquity. And when it comes to supporting chronology, numismatics is probably the best evidence. It would be impossible for a forger of history to bury hundreds of thousands of matching coins all over Europe.