The first four Caliphs who ruled after the death of Muhammad peace be up on him are often quoted as the Khulafah Rashidun
Abu Bakr
Abu Bakr (Abdullah ibn Abi Qahafa) (Arabic: عبد الله بن أبي قحافة; Transliteration: ‘Abdullāh bin Abī Quhāfah, c. 573 CE unknown exact date 634/13 AH) was a senior companion (Sahabah) and the father-in-law of the Islamic ProphetMuhammad peace be upon him.
He ruled over the Rashidun Caliphate from 632-634 CE when he became the first Muslim Caliph following Muhammad’s death.
As Caliph, Abu Bakr succeeded to the political and administrative functions previously exercised by the Prophet, since the religious function and authority of prophethood ended with Muhammad’s death according to Islam.
Abu Bakr was called Al-Siddiq (The Truthful)and was known by that title among later generations of Muslims.
Umar ibn al-Khattab
Umar (Arabic: عمر بن الخطاب; Transliteration: `Umar ibn al-Khattāb, c. 586–590 – 644) c. 2 Nov. (Dhu al-Hijjah 26, 23 Hijri) , was a leading companion and adviser to the Islamic prophetMuhammad, and became the second Muslim Khalifa after Muhammad’s death and ruled for 10 years.
He succeeded CaliphAbu Bakr on 23 August 634 as the second Caliph, and played a significant role in Islam.
Under Umar the Islamic empire expanded at an unprecedented rate ruling the whole Sassanid Persian Empire and more than two thirds of the Eastern Roman Empire.
His legislative abilities, his firm political and administrative control over a rapidly expanding empire and his brilliantly coordinated multi-prong attacks against the Sassanid Persian Empire that resulted in the conquest of the Persian empire in less than two years, marked his reputation as a great political and military leader.
He was killed by a Persian captive
Uthman ibn Affan
`Uthman ibn `Affan (Arabic: عثمان بن عفان) (c. 579 – 17 July 656) was one of the companions of Islamic prophet, Muhammad peace be upon him.
Uthman was born into the Umayyad clan of Mecca, a powerful family of the Quraish tribe.
He was a companion of Muhammad who became caliph at the age of 70.
Under his leadership, the empire expanded into Fars in 650 (present-day Iran), some areas of Khorasan (present-day Afghanistan)in 651 and the conquest of Armenia was begun in the 640s.
His rule ended when he was assassinated.
This work was undertaken due to the vast expansion of Islam under Uthman’s rule.
Ali ibn Abi Talib
After the death of Uthman, Medina was in political chaos for a number of days. Many of the companions approached Ali to take the role of Caliph, which he refused to do initially.
Ali then transferred his capital from Medina to Kufa, the Muslim garrison city in what is now Iraq.
The capital of the province of Syria, Damascus, was held by Mu’awiyah, the governor of Syria and a kinsman of Uthman.