You won't find many terms older than Czar. It's derived from Caius Julius, known as "Haircut" or Caesar. (probably pronounced Kaisar)
He did pretty well in miltiary politics and his heirs and sucessors adopted his name with the result that it came to mean Emperor.
The dominance of the Roman Empires passed the term to many other cultures, Via Greece to Russia, as 'Czar'. Via the Holy Roman Empire to Germany as 'Kaiser'. The Islamic ruler of what is now Turkey and the Balkans called himself 'Kaizar y Rhum"-Emperor of Rome.
"Emperor", by the way comes from 'Imperator'- General, a title bestowed on a victorious commander by his surviving troops (happy at having survived). The traditional title for a ruler of many lands would be 'King of Kings' or 'High King'.
Given all of this, it is clear that many of these titles would be unconstitutional in the USA, or treasonable in the UK.
But the title of "The High King of Cars" or the "King of Drugs Kings" would look pretty impressive on your CV.
Cheers
Dave