Where does “pp” come from?

I can't write this etymology summary because the chain provided contains circular references and unexplained jumps that don't form a coherent etymological path. The chain lists "English poster," "English post," and "English per" multiple times without clear progression, and the meaning of "pp" is marked unknown, making it impossible to trace a legitimate sense development or explain how these elements connect. A reliable etymology requires a clear, non-circular sequence with established connections between languages.

pp (English): plural of p; abbreviation of pages; Initialism of...