Quote Originally Posted by Lord Condormanius
not to sound stupid, but...How does one do this?
Edit the "timescale 2.0" line in the descr_strat.txt to be "timescale 0.5".

The file is usually located in:

C:\Program Files\SEGA\Medieval II Total War\data\world\maps\campaign\imperial_campaign

Double clicking the file will open it in notepad. But note that the file is read-only - you need to remove that property in order to save edits (right click on the file, choose properties and untick "read-only").

Obviously, make a backup copy of the file first before messing with it - just in case.