Muawiyah made the office of Caliph hereditary.
After the death of the Prophet (SAW), Hazrat Abu Bakr Siddique (RAU) was chosen the Muslim Ruler. His title was 'The Caliph of the Rasool'. All the subsequent Caliphs were called Ameer-ul-Momineen. The title is generally called 'Caliph'.
Caliph meaning the representative of God on earth
maybe caliph?
No, that title is "Caliph", not Czar.
The title of the Islamic Empire was Caliphate. The Caliph was called Amir-ul-Momineen.
Caliph
No. The title taken by Muslim rulers who assert religious authority is typically Caliph or Ayatollah. The Czar was a term used to designate the Russian Kings.
Caliph (or Khalifa in Arabic)
The third Caliph Uthman Ibn Affan.
A Caliph or khalifa is a sort of religious dictator, an Islamic ruler, considered to be the political-religious leader of an Islamic community of believers, ruling in accordance with Islamic law.
According to the majority of the Muslims, it is justified. The Shias don't think so.