> But historically, wasn't there a fair period of time between Haskell insisting on referential transparency (and therefore not allowing traditional mutable state) and monads being introduced as a way to deal with it? That was my understanding of the history.

Yes, although there were solutions in the meantime. I/O was performed in the original version of Haskell through input-output streams and continuation passing style. It turns out that both approaches could have been given monad interfaces if "monad" as an abstraction had been understood at the time, but it wasn't, so they had ad hoc interfaces instead.

> And if so, then it seems fair to say at least that monads were a way to get around the limitations imposed by a desirable feature of the language...

I mean, sort of, but that seems more of a judgement than a fact. Would you say that function calls in C were a way to "get around the limitations imposed by not allowing global jumps"?

In both cases I'd just say they're a useful abstraction that lets you achieve a well-specified goal whilst preserving some desirable language property.

> Would you say that function calls in C were a way to "get around the limitations imposed by not allowing global jumps"?

If C had started with a rule against global jumps, and only figured out function calls later, then yes I would say that.