When “one of” many things is itself plural
There are all sorts of things I believed in then which I don’t believe in now, and language rules set in stone is/are (?) one of them.
My feeling is that ‘is’ is OK here, since ‘language rules set in stone’ is one of a list of things I once believed in, and ‘are’ would grate with ‘one’. What do you think?
NB This is purely a grammar question, not one about my beliefs, which I know some of you will strongly disagree with. There will no doubt be plenty of other occasions to cross swords over them.