The religious-political disturbances of the first Islamic century all centered on the vital question of who should be the Khalīfa, the Prophet's Caliph or successor, or as he is often called, the Imām, the "leader" of Muslim religious life. The two terms are used interchangeably, with a few exceptions.
A very important view is that expressed by the Shāfi'i legist al-Māwardī (died A.H. 450/A.D. 1058). The Caliph is seen as the sole legitimate Muslim authority, and all other authority is legitimatized by delegation of power from him.
In his book on the rules governing the exercise of power al-Māwardī is moved more by theoretical than by practical considerations. The ‘Abbāsī Caliph in his days, from being the ruler of a world-wide Muslim empire, had become little more than the prisoner of a Shī‘ī Persian family of military dictators, the Buwayhīs, and there were rival Caliphs in Cairo (the Fāṭimīs) and Cordoba (the Spanish Umawīs). Still, al-Māwardī saw his Caliph as the fountainhead of all validly exercised power in Muslim lands.
The Imāmate is placed on earth to succeed the Prophet in the duties of defending the Religion and of governing the world (al-dunyā). To invest with authority that person in the Community who performs these duties is a religious obligation, according to the Concensus of (Sunnī) 'Ulama', even though al-Aṡamm (the Mu‘tazilī) stands alone against them, and opinions differ as to whether this duty is necessitated by Reason or by Law. One party has held that it is necessitated by Reason, since it pertains to intelligent beings to submit themselves to a leader who will keep them from wronging
one another, and will judge between them in their contentions and disputes, so that if there were no supremacy there would be anarchy and men would be a confused rabble. Al-Afwa al-Awdī, the pre-Islamic Arabian poet, has this to say:
According to another party, it is necessitated rather by the Law, which goes beyond Reason: so that Reason would not demand it if the service of God did not demand otherwise, for Reason only demands of intelligent men that they forbid themselves to commit wrongs against each other or cut relations with one another and that they act in accordance with justice, in equality and friendly conduct; to follow their own reason and not the reason of another. However, the Law has come to give jurisdiction to its delegate in the Religion. For God, the Mighty and Glorious, has said: "Oh ye who believe, obey God and obey the Messenger, and those set in authority (Ūli al-Amr), among you" (4:58), so that it is a religious obligation for us to obey the ones set in authority among us, and these are the Imāms reigning over us.
Hishām ibn ‘Urwa relates on the authority of Abū Ṡālih from Abū Hurayra that the Messenger of God, the benediction of God and peace be upon him, said: "Other rulers will govern you after me. The pious will govern you with his piety, and the libertine with his immorality. Listen to them both, and obey them in everything that conforms with the truth. If they do well, it is to their credit and yours, but if they do evil, it will be to your credit and their discredit." . . .
As for those persons fitted for the Imāmate, the conditions relating to them are seven.
1. Justice, in all its characteristics.
2. Knowledge requisite for independent judgements (ijtihād) about revealed and legal matters.
3. Soundness of the senses in hearing, sight, and speech, in a degree to accord with their normal functioning.
4. Soundness of the members from any defect which would prevent freedom of movement and agility.
5. Judgement conducive to the governing of subjects and administering matters of general welfare.
6. Courage and bravery, for protecting Muslim territory and waging the Holy War (jihād) against the enemy.
7. Pedigree: he must be of the tribe of Quraysh, since there has come down an explicit statement on this and the concensus has agreed. There is no need to take account of Ḍirār ibn ‘Amr, who stood alone when he declared all men eligible. The Prophet said, "The Quraysh have precedence, so do not go before them," and there is no pretext for any disagreement, given this clear statement delivered to us, and no word that one can raise against it. 16
With time, the Caliphal government at Baghdad was destroyed by the Mongol invasions (1258). Descendants of the ‘Abbāsīs were honored with the title and a pension by the Mamlūk Sulṭāns of Cairo (until 1517), as living symbols of Muslim unity in a defunct empire. It was in this context that the great scholar and historian Ibn Khaldūn lived and wrote (born A.H. 732/A.D. 1332, died A.H. 808/A.D. 1406). While his masterpiece, the "Introduction" (Muqaddima) to his "History" is not a fiqh book, Ibn Khaldūn was a prominent Mālikī professor and judge. His view is a legal one, and has been widely accepted in later times. In effect, he is saying that every ruler who rules Islamically is, in a sense, the successor or Caliph of the Prophet.
The Meaning of the Caliphate: Political laws consider only worldly interests. "They know the outward life of this world" (Qur’ān 30:7). On the other hand, the intention the Law-giver has concerning mankind is their welfare in the other world. Therefore, it is necessary, as required by the religious law, to cause the mass to act in accordance with the religious laws in all their affairs touching both this world and the
other world. The authority to do so was possessed by the representatives of the religious law, the prophets. (Later on, it was possessed) by those who took their place, the caliphs.
This makes it clear what the caliphate means. Natural royal authority means to cause the masses to act as required by purpose and desire. Political (royal authority) means to cause the masses to act as required by intellectual (rational) insight into the means of furthering their worldly interests and avoiding anything that is harmful (in that respect). The caliphate means to cause the masses to act as required by religious insight into their interests in the other world as well as in this world. (The worldly interests) have bearing upon (the interests in the other world), since according to the Law-giver (Muhammad), all worldly conditions are to be considered in their relation to their value for the other world. Thus (the caliphate) in reality substitutes for the Lawgiver (Muhammad), in as much as it serves, like him, to protect the religion and to exercise (political) leadership of the world. This should be understood and be kept in mind in the following discussion. . . .
The institution is called "the caliphate" or "the imāmate." The person in charge is called "the caliph" or "the imām."
In later times he has (also) been called "the sultan," when there were numerous (claimants to the position) or when, in view of the distances (separating different regions) and in disregard of the conditions governing the institution, people were forced to render the oath of allegiance to anybody who seized power. 17
125:16 Al-Māwardī. Al-Ahkām al-Sultānīya (Cairo, 1909), pp. 3, 4.
125:17 p. 246 Ibn Khaldūn, The Muqaddima, Vol. I, pp. 387, 388.