Long long ago ...
Long long ago, so long ago, how long ago, that long ago, that nobody knew how long ago, as long as can be.
This was how we used to remind people of something that had been said to them earlier and about which they had forgotten!
E.g.
Other person: Really? When did you say that?
Us: Long long ago, so long ago, how long ago, that long ago, that nobody knew how long ago, as long as can be.
Initially, it used to only be long long ago, so long ago. The other phrases got added as the year went by!