In 1200, the area earlier and later known as Persia was under the rule of the Great Seljuks. 1205 however, Muhammad II of Choresm conquered it and made himself Shah. From now on, Persia was a part of Choresm. 1377-81, the Black Death hit Persia. However, the same fate struck Choresm 1378-85, preventing a reconquest of Persia. Since 1400, the Shi'ite rulers of Persia started persecuting the Ismailite minority. The Assassins fought back, but had lost their edge.