Complex sentence: The story was originally written as a spoof history or possibly a future history, written as it is by a historian in the year 2073 about events taking place in 1973,10 years from its actual publication date.
Split into simpler sentences: The story was originally written as a spoof history or possibly a future history. The narrator is a historian writing in the year 2073 about events taking place in 1973,10 years from the story's actual publication date.