I have emacs 24.1.1, which comes with GNU's python.el in byte-compiled form at emacs/24.1/lisp/progmodes.
I downloaded Fabian Gallina's python.el (note the same name) and placed it at emacs/site-lisp, which is part of emacs' load-path.
When I edit a Python file, it is Gallina's mode which is loaded, NOT GNU's. However, I have not put (require 'python) in my .emacs file, despite what Gallina's documentation suggests.
Why is this? Why does Gallina's python.el take precedence over GNU's? Why does it get loaded without (require 'python)?