https://en.wikipedia.org/wiki/Holy_Nail
That said, I'd like to know the carbon date on those wooden fragments.
In between comes the Protestant Reformation, more than a century of religious wars across all of Europe where one side in many cases actively sought to destroy relics and the gradual conversion to Islam of many densely populated Christian areas.
A catalogue from the 1870 is next to worthless for telling us how many relics existed in the early 1500s.
I thought we were talking about how many are on display? What does the number of fragments that existed in the 1500s matter?
There are far less now that Protestants spent a century destroying purported fragments.
'Master!' I said, shocked.
'So it is, Adso. And there are ever richer treasuries. Some time ago, in the cathedral of Cologne, I saw the skull of John the Baptist at the age of twelve.'
'Really?' I exclaimed, amazed. Then, siezed by doubt, I added, 'But the Baptist was executed at a more advanced age!'
'The other skull must be in another treasury,' William said, with a grave face. I never understood when he was jesting.” ― Umberto Eco, The Name of the Rose
Frankly though, I consider authenticity overrated.