autocrat

noun3

1. •
   An absolute ruler with infinite power.

   • Your salary is high; you are to have apartments in the house; and to be the autocrat of the library, where, I shrewdly suspect, your reign will be undisturbed. — 1837
2. •
   A title borne by some such monarchs, as in Byzantium and tsarist Russia.
3. •
   Until the 20th century, a favorable description of a ruler who was connected with the concept of lack of conflicts of interest and an indication of grandeur and power.