Amīr al-Mu'minīn usually translated Commander of the Faithful or Leader of the Faithful, is the Arabic style of Caliph

Caliph

The Caliph is the head of state in a Caliphate, and the title for the ruler of the Islamic Ummah, an Islamic community ruled by the Shari'ah. It is a transcribed version of the Arabic word   which means "successor" or "representative"...

s and other independent sovereign Muslim

Muslim

A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...

 rulers that claim legitimacy from a community of Muslims. It has been claimed as the title of rulers in Muslim countries and empires and is still used for some Muslim leaders.

Use

The title Amir al-Mu'minin is a divinely given name to Ali ibn Abi Talib.
Many other caliphs have been given the name as well such as Umar ibn al-Khattāb, the second of the Four Rightly Guided Caliphs

Rashidun

The Rightly Guided Caliphs or The Righteous Caliphs is a term used in Sunni Islam to refer to the first four Caliphs who established the Rashidun Caliphate. The concept of "Rightly Guided Caliphs" originated with the Abbasid Dynasty...

 and Uthman ibn Affan.

The title is also used by Shia Muslims to refer to their first Imam

Imam

An imam is an Islamic leadership position, often the worship leader of a mosque and the Muslim community. Similar to spiritual leaders, the imam is the one who leads Islamic worship services. More often, the community turns to the mosque imam if they have a religious question...

, Ali ibn Abi Talib.

It has also been adopted by various Caliphs of the succeeding Umayyad

Umayyad

The Umayyad Caliphate was the second of the four major Arab caliphates established after the death of Muhammad. It was ruled by the Umayyad dynasty, whose name derives from Umayya ibn Abd Shams, the great-grandfather of the first Umayyad caliph. Although the Umayyad family originally came from the...

 and Abbasid

Abbasid

The Abbasid Caliphate or, more simply, the Abbasids , was the third of the Islamic caliphates. It was ruled by the Abbasid dynasty of caliphs, who built their capital in Baghdad after overthrowing the Umayyad caliphate from all but the al-Andalus region....

 dynasties, as well as by some contemporary Arab

Arab

Arab people, also known as Arabs , are a panethnicity primarily living in the Arab world, which is located in Western Asia and North Africa. They are identified as such on one or more of genealogical, linguistic, or cultural grounds, with tribal affiliations, and intra-tribal relationships playing...

 monarchs.

For current use, see below.

Sunni view

Sunni view that Umar was the first person to be given the title:

Shi'a view

Shi'as view that Ali, the prophet of Islam's son-in-law and the progenitor of Muhammad's only continuing lineage, was given the title during Muhammad's era.

Shi'as believe the title is exclusive to Ali bin abi Talib. Being called the commander of the faithful does not entail only political authority, but spiritual and religious authority as well.

Some sunni Muslims refer to anyone in political power as Amir Al-Mumenin, the caliphate of past Islamic dynasties, and that both the present day kings of Morocco and Saudi Arabia can be referred to by this title. This is viewed in the Shi'a perspective as a wrong and unworthy use of the title.

Current positions that officially use this title

• According to the Moroccan
  Morocco
  Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
  
   constitution
  Constitution
  A constitution is a set of fundamental principles or established precedents according to which a state or other organization is governed. These rules together make up, i.e. constitute, what the entity is...
  
   the King of Morocco is also Amir al-Mu'minin.
• The Sultan of Sokoto.
• The spiritual leader and Caliph
  Khalifatul Masih
  Khalifatul Masih sometimes simply referred to as Khalifah is the elected spiritual leader of the worldwide Ahmadiyya Muslim Community and is the successor of Mirza Ghulam Ahmad of Qadian...
  
   of the worldwide Ahmadiyya Muslim Community
  Ahmadiyya Muslim Community
  The Ahmadiyya Muslim Community is the larger of two communities that arose from the Ahmadiyya movement founded in 1889 in India by Mirza Ghulam Ahmad of Qadian . The original movement split into two factions soon after the death of the founder...
  
   is also called Amir al-Mu'minin.

Others who have used the title

• Various Caliph
  Caliph
  The Caliph is the head of state in a Caliphate, and the title for the ruler of the Islamic Ummah, an Islamic community ruled by the Shari'ah. It is a transcribed version of the Arabic word   which means "successor" or "representative"...
  
  s.
• The founder of the Taliban  Mohammed Omar
  Mohammed Omar
  Mullah Mohammed Omar , often simply called Mullah Omar, is the leader of the Taliban movement that operates in Afghanistan. He was Afghanistan's de facto head of state from 1996 to late 2001, under the official title "Head of the Supreme Council"...
  
   was called this by his followers, after he donned the Cloak of the Prophet
  Mosque of the Cloak of the Prophet Mohammed
  The Shrine of the Cloak is located adjacent to the Friday Mosque in Kandahar, Afghanistan. It contains a cloak that was once worn by Islam's Prophet Muhammad, which is widely considered as one of the holiest Islamic sites in Afghanistan, and even considered by some as the "heart of Afghanistan".The...
  
  . Ayman al-Zawahiri still occasionally refers to him as the Amir al-Mu'minin in his radio addresses.