A replica of the Four Horses of St. Mark's sit atop the Arc de Triomphe  du Carrousel in Paris.

A colleague in Italy emailed Tompkins and told him to check out the book. He popped into a bookshop in Matakana, north of Auckland, and found the relevant page. 

"I went back and looked at the article I wrote in 2011 and there it was, that passage. It's a small feeling of personal satisfaction that some work you've done has been read by someone else and then turned up in a place that I never would have expected to see it." 

Tompkins says Brown gets some of his facts slightly wrong - Brown says Napoleon displayed the horses on top of the Arc de Triomphe, when in fact they were displayed on a smaller arc nearby. 

He is also definitive about where and when the statutes were created, when no-one knows for sure. 

But that doesn't bother Tompkins too much. "He's very clever in the way he creates a feeling that he's revealing important secrets, where none of it's much secret at all. You get the feeling you're on this enormous treasure hunt."