What does "the darkest of nights" mean?

Over at German.SE we have a question involving "the darkest of nights". I would like to know what this expression actually means, but I didn't find it in an online dictionary (e.g. leo.org, dict.cc, Cambridge Dictionary).

So what does this expression mean? Is it a figure of speech? I can imagine at least two meanings: It's the time of a particular night when it is darkest, or it's the darkest of a (not specified) number of nights.

Solution 1:

German.SE was discussing superlatives (in the sense of grammar).

In that context, "the darkest of nights" simply means "a night darker than any other (of an unspecified number)."

You can use it in a literal sense, as in "it was the darkest of nights when the power grid failed and the moon was new."

Or, you can use it a figurative sense to convey that it was a night of great sorrow or some other sense of the word dark.

Solution 2:

The darkest of nights could be a metaphorical expression to mean the very worst of bad times. Of course it could be interpreted literally to mean the darkest night among many nights.