Ancient Greece
Collect the heads of Robin Hood (Sherwood), Joe Thompson (San Francisco) and Grendel (Beowulf). Heads are heavy -- you may need help carrying them. Go the Realm of the Dead in the Aegean Sea. (To pass the Cockatrice you must either wear a mirror shield or obtain the Blessing of Hades. To obtain the mirror shield, see the Dexterity Quest. To obtain the Blessing of Hades see the Favor Quests section.) Go to Hades. ASK HADES DEATH and give him the heads, one by one. You learn MRTI!
***Nestor has hinted that you can get mrti inside of JCE at 50, please post details if you know them.