Ibadism or Ibadiyyah derives its name from Abdullah ibn Ibad of the Banu Tamim.  It originated from the Kharijites. This sect came into being when Abdullah bin Ibadh separated from Khawarij (or Kharijites). He renounced the Kharijites completely in the year 65 A.H.  and rebelled against the Zubair family. Since he was a jurisprudent, he has been referred to in the Ibadiyya sources as the leader of researchers, the leader of the nation and Muslims.
The reason Abdullah bin Ibadh is seen as a moderate person is because he reconciled with Abdul Malik b. Marwan, the Amawid Caliph and that he was against Abdullah b. Zubair.  The policy he adopted was also followed by his successor, Abu al-Sha'tha Jabir b. Zaid Azdi. Abu al-Sha'tha was from Oman. He died in the year 100 of the Islamic calendar after Abdullah bin Ibadh's death. Abu al-Sha'tha Jabir had a friendly tie with Hajjaj b. Yusuf Thaqafi but the friendly relation did not last long as Hajjaj embarked on killing the followers of the Ibadiyya sect like other Kharijites. During his time, most of the Ibadis were banished to Oman.
Ibadis in Basra:
Jabir had a student who was Iranian (Persian) by origin. His name was Abu Ubaidah Muslim bin Karima Tamimi and he was considered to be amongst the jurisprudents and scholars of that sect. After Jabir's death, he became his successor and the followers of the Ibadiyya sect visited him in Basra from all over the world. When the Amawid caliphate was claimed by Umar bin Abdul Aziz, the leaders of the Ibadi movement grew hopeful of attracting the attention of the caliphate. Umar bin Adul Aziz allowed Ayas bin Muawiyah Ibadi to become Basra's judge. An educational center was established in Basra where the Kharijite students gathered to acquire education.[1]
After the downfall of the Amawids and the coming to power of the Abbasids, Mansoor Dawaneqi maintained good ties with Ibadis for some time. But then following Abu Ubaida's death, the Ibadis began to decline in Basra with Ibadi community centers created in Kufa, Hijaz, Hadramaut, Yemen and Oman.[2]
Ibadiyya in Oman
The Kharijites of Oman began to get inclined towards the Ibadiyya movement from the end of the first century onward. The main individual who played a key role in the people's inclination to Ibadiyyah was Jabir bin Zaid and a few other Ibadi scholars whom Hajjaj bin Yusuf had banished to Oman. Thereupon, a rebellion led by Jalandi bin Masud took place there. The rebellion was taken as far as to Hadramaut and Yemen. However, eventually, in the year 134 A.H. the insurgency was quelled by the Abbasid army led by Khazim bin Khuzaimah.
When it comes to the important role of Oman in the Ibadiyya history, there is a famous proverb which says:
«باض العلم بالمدینه و فرّخ بالبصره و طار الى عمان»
The proverb means that Ibadiyyah lay eggs in Medina and it hatched out in Basra and then it flew to Oman.
Some of the leaders of the Ibadi movement of Oman were called Wāli (governor) or mutaqaddim (leader).[3]
Ibadiyya in Tunis:
The first person to invite to Ibadiyya in Tunis (or Maghrib) was Salāmah bin Saeid. He was amongst the masters (Mashayekh) of Basra. He preached the Ibadi sect in North Africa in the early second Islamic century. Thereupon, we come across a man named Abdullah b. Masud Tajyibi who spread this movement in Libya and Tripoli. He was spreading this religion among Barbar tribe (Hawwarah).
After him, Ismail b. Ziad Nufusi was designated by Ibadi Barbar tribes of Tripoli as "Imam al-Difa' (lit. defense leader) and he was killed in the year 132 A.H. His death marks the end of the Ziadi government in Tripoli.[4]
After Ismail b. Ziad, a man named Abdur Rahman b. Rustam, Persian by origin, established an Ibadi government in Qirwan. Then he conquered the city of Tahirt and in the year 160, he was appointed as the leader of the Ibadiyya sect in North Africa. During the period of Ibn Rustam Abdul Wahhab b. Abdur Rahman and Aflah b. Abdul Wahhab, the Ibadiyya sect rose to the peak in Tunis. It was only in the sixth hegira century that, after Fatimids took over North Africa, the Ibadiyya state began to decline in that region. The Ibadis in North Africa chose to live aloof in several regions and they have continued to survive there as of the present time.
Ibadi Sects
The most important Ibadi branch is known as "Wahabiyah" which considers itself as a religion inviting others to embrace it.
Another sect affiliated to Ibadiyya is Harithiya whose founder was Hamzah al-Kufi. He was a follower of the Mu'tazilites in the issue of "fate and predestination". This sect is linked to an Ibadi scholar named Harith bin Mazid.
Another sect is Tarifiyyah who are the followers of Abdullah bin Tarif, one of the companions of Imam Talib al-Haqq. This sect was established in south Arabia in the year 129 A.H.
Other sects[5] affiliated to Ibadiyya are Nakar, Nafathiyya, Khalafiyya, Umariyya, Hasaniyya, Sakkakiyya, Hafsiyya and Yazidiyya.[6]
Ibadiyya Beliefs
They constituted the moderate branch of the Kharijites. Unlike the Azareqa who were from the extremist Kharijites, the Ibadis considered their opponents from the People of Qibla to be unbelievers, not polytheists.
They believed in the permissibility of marriage with their opponents and inheritance from them. They believed that those who committed the major sins are monotheists, even though they are not believers (momeen). Unlike other Kharijites, they did not consider the Commander of the Faithful, Ali (A.S) to be their imam (leader) nor did they consider themselves as muhajir (migrants). They were saying that whenever when we are absolved of duty, the world will also cease to exist.
They allowed the testimony of their opponents on their friends saying that whoever committed a major sin is a person who rejects divine blessings but he is not a kafir milli (absolute ideological disbeliever).
Regarding their imams, they believed in two visible and hidden manners saying that an imam could be hidden for a long time and make his presence known in an appropriate time. Then at that time, he is called the "leader of allegiance" and "Imam of Appearance".
Ibadis like other Muslims believe in the Quran and Sunnah as the sources of Islamic laws but they also consider "ra'y" (opinion) as a valid source of legislation rather than "ijma" (consensus). They say that God forgives the minor sins but He does not forgive greater sins except through repentance.[7]
Note: Given the fact that the Kharijites were strongly opposed to Imam Ali (A.S) and as evidenced by some reports about Ibadiyya, in the past they labeled the Commander of the Faithful and some of the companions of the Holy Prophet (S)[8] as infidels but it is not known, if the followers of Ibadiyya still maintain the same belief or not.[9]

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