Where does the word “caliph” come from and What does caliph mean?

After the death of Mahomet in 632, the question immediately arose among his loyal adherents who should serve as his representative.

The leading spirit among them was Omar who, as a young man, had opposed the Prophet, but who later was to be one of his ablest supporters.

Omar decided, however, that the honor should first be bestowed upon the man who had been Mahomet’s sole companion in the flight from Mecca (the Hegira) and who subsequently became his father-in-law. This was Abu-Bekr, long known as “the faithful.”

Abu-Bekr thus became the first “successor,” a word that, in Arabic, is rendered khalifah and which in English became caliph. (See also ADMIRAL.)