Just a word about my label "congregation".
I have in mind an early translation of Matt 16:18. I think it may have been Coverdale's. Instead of 'church' he rendered the Greek as 'congregation'. I had thought that it was Wycliffe's, but not so, as you will see if you click the link.
It makes all the difference.
We bring our modern experience of 'church' as an organisation to the text, and so misread it, allowing the Roman misreading to have some air.
But just let Coverdale's translation (if that is the one I'm recalling) sink in:
You are Peter and upon this rock I will build my congregation.