I wrote a reply to this, but it didn't get through, so I'll try again. Hopefully, this time it works...
I believe that it was Josef of Nazareth who built the staircase, but the writer of the article below is obviously of a different kind. Just thought
that I should balance the thing with an article made by a sceptic.
The argument about the iron support seems stupid, for it looks as if this element has been added later, by someone else. I feel it brakes aestetically
with the overall design concept quite violently. And that a carpenter with such qualities in woodwork, would have been just as gifted within ironwork.
Besides. Why would he have used iron as support when he didn't even use iron nails? Anyway. Here it is: