There is a well known phrase "скатертью дорога" which is sort of caustic version of "good riddance". There's also a common knowledge that this phrase initially meant something exactly the opposite from what it means now, namely, it was sort of Russian "Bon voyage". And then this original meaning gradually faded away and finally what was actually the ironical rethinking became the main usage.
The thing is I'm failing to find any sources on this being true - there's no evidence of "скатертью дорога" ever used as some positive wish.
My question would be - when exactly this phrase came to usage and what exactly it meant back then?
Here's the earliest reference I was able to find. This is from a play written by Ivan Mikhailovich Dolgorukov, who lived at the end of XVIIIth - beginning of XIXth century:
Дурылом: Любовь чума в семье, в которой девок много
Лестигон: Любви счастливый путь, и скатертью дорога!
It's actually already quite ironical.
In phraseological dictionary "Ходячiя и мѣткiя слова"(Mikhelson, in modern orthography "Ходячие и меткие слова") one can find:
The positive wish meaning is not mentioned at all. In comments there are some examples of positive usage dating back to XIXth century. While those are nice finds, that by itself proves nothing. For instance, this could be a later development.