>It doesn't seem like there's major doubt that the Cossacks sent a rude retort to a surrender demand
There's no doubt that they did that. We have multiple documented responses, some of which are quite witty I'll add. (If you remove the old-fashioned tone of voice from the translations and speak them as someone would today, even the drier ones can be fairly amusing.)
There are also embellished or fabricated responses even in modern times.
The question is - which of those is this letter? I don't think we can rule out any possibility based on the information we have available. We simply have a gap of a hundred-odd years in which we can find no surviving written evidence that people talked about it. I don't think that's evidence enough that it didn't exist.
The issue here might be the fact that the Wikipedia article is about the painting, but includes a purported text of ‘the letter’ - presumably of the letter in the painting - but there’s no citation given for where that particular text is sourced or it’s translation.
No, that's not the issue here. There are various texts for the letter going back to the 1800s. The issue is that there is no record of the letter between 1676 and the 1800s, causing some Redditors to believe it was a fabrication of that time.
> If you remove the old-fashioned tone of voice from the translations and speak them as someone would today
I think that's almost wholly because of the the "thou", which was added to distinguish from the polite plural "you", but maybe it shouldn't have been. I doubt anyone would have mistaken "fuck your mother" for the polite plural.
There's no doubt that they did that. We have multiple documented responses, some of which are quite witty I'll add. (If you remove the old-fashioned tone of voice from the translations and speak them as someone would today, even the drier ones can be fairly amusing.)
There are also embellished or fabricated responses even in modern times.
The question is - which of those is this letter? I don't think we can rule out any possibility based on the information we have available. We simply have a gap of a hundred-odd years in which we can find no surviving written evidence that people talked about it. I don't think that's evidence enough that it didn't exist.