No leaders can have IDs above 20000, that will make the game crash.
Copying leaders into the save game, while changing ID numbers to 16001 and on should work, compare with other nations to see if format changes from leader file to save-game file.
All leaders in game, as monarchs, are gathered from save-file, only events are gathered from original files.
Try and try again
Good luck.
Copying leaders into the save game, while changing ID numbers to 16001 and on should work, compare with other nations to see if format changes from leader file to save-game file.
All leaders in game, as monarchs, are gathered from save-file, only events are gathered from original files.
Try and try again