I reckon it was a personal view, reflecting his thinking that the old Europe of the empires had expired, maybe a bit annoyed no more reasonable claim of continuity or successor to the Roman Empire could be made, with the extinction of the German and the Russian ones.

In fact he was so adamant about it, he effectively terminated his 4 or 5 volumes work "History of Europe" in 1914, even though he had the entire 20th century to analyse.

What I wonder is if this point of view is shared by more historians or was this specific one that was particularly nostalgic or longing about Rome.