I love this reference to Thucydides historical accounts. I had to look up who Thucydides was but this part makes so much sense after looking that up. Thucydides wrote a great account of the Peloponnesian War and all the atrocities and devastation that occurred during it. Auden is referencing this because we did not learn from this and the peace that was there without war is being broken and the suffering is happening yet again. This is becoming another significant event in history and Auden is saying this by referencing Thucydides.

Why is it just "mere anarchy?" In my experience anarchy is usually a pretty serious and violent thing, Anarchy is not something you see described as "mere." I think that he describes it as mere because it is not as amazing or serious as the second coming that the poem is about, it is just merely a step along the way to the final product.

I find the description of nature very interesting considering other authors we have read have always had a very strong aspect of nature for the most part, especially in the romantic unit. However this brings in aspects of personification with the white hair of the waves and paints a picture for the reader through this unlike "Mont Blanc" which is very literal and describes nature as it is without any sort of personification in my opinion.

I feel like this is another reference to death and that his head being brought in upon a platter is like his life is being served up to him and that his time is ending. However he states that he's not a prophet and to lighten the mood rhymes it with it not being a great matter. So he is trying to dissuade himself from thinking that his life is ending by going along with he doesn't know what he is talking about.