Abu Bakr (R), Omar (R), Usman (R) and Ali (R)
All the first Four Caliphs were chosen in different ways. Later on it became a kind of Kingship, son following the father.
First 4 Caliphs were not missionaries to Africa , but many other companions of prophet were .
There was no rule of caliphs in ancient Rome. The caliphs emerged after the fall of Rome
The first four Caliphs in Islam are regarded as the Khulfa-e-Rashidun or The Four Rightly Guided Caliphs. These caliphs are regarded as the most famous and comprise of Hazrat Abu Bakr, Hazrat Umar, Hazrat Usman as well as Hazrat Ali.
The Umayyad Caliphate came after the four Rightly-Guided Caliphs.
they ruled differently
None. Caliphs came to power in the Medieval Period. As for the Medieval period, the Caliphs were the leaders of the Muslim Empires called Caliphates. The four first Caliphs were called the Rightly-Guided Caliphs and they also had some religious authority in Islam. Because of the barbarity of the Umayyad Caliphs, the religious authority left the Caliphs and vested in the local Imams. Religious authority would return to the Caliphs in the mid-1500s in the Ottoman Empire until Atatürk abolished the Caliphate in 1936.
to northwest europe
they were the damascus
they ruled differently
Quran and Hadith .
The first main 4 Caliphs (who are called the 4 orthodox caliphs) are:HAZRAT ABU BAKR SIDDIQUE (Raddi Allah Unho)The First Caliph of IslamHAZRAT UMAR FAROOQ (Raddi Allah Unho)The Second Caliph of IslamHAZRAT USMAN GHANI (Raddi Allah Unho)The Third Caliph of IslamHAZRAT ALI MURTZA (Raddi Allah Unho)The Fourth Caliph of Islam