This mod allows you to turn any three Duchies into a Kingdom, and any four Kingdoms into an Empire.
Titular Kingdoms and Empires also gain the ability to prevent direct and secondary vassals from warring each other or anyone with high enough crown law.
Credits:
http://forum.paradoxplaza.com/forum/showthread.php?589622-Mini-Mod-Rise-of-Empires-(Empire-creation-mod)