The different madhahib
Various schools of thought have arisen in Islam. schools of thought like: Maliki, Hanbali, Shafi'i are well known. But there are also schools of thought that are less well known, such as: Thawri, Awza'ee, Layth and others.
Through time there have been four main madhabs chosen by people. So it is not the case that only those exist, but that they are most followed.
Some see the main madhabs as five, including Dhahiri. This madhab is not well known, because it originated quite late. Its followers are also few.
The school of Abu Hanifa is regarded as the first school of thought that is established. The founder, Abu Hanifa, lived in Kufa (city in Iraq) and was of Persian origin. The madhab is best known in large parts of Asia. In countries such as India, Pakistan and Turkey this school of thought is most strictly followed.
Many who ascribe to this madhab do not have a Sunni background. They often belong to the groups: Murjiah, Dheobandi, Ash'ari or Maturidi.
These groups occur because the place which in the Madhab is populair. The Murjiah followers of Hanafi madhab take their creed from its founder, Abu Hanifa.
The madhab is known for its frequent use of Qiyas (analogy) and Raiyy (opinion). This created many differences in the school with that of the schools of thought that came later (which used the Qur'an and Sunnah first).
The school of thought of Malik ibn Anas (Imam Malik) came right after that of Abu Hanifa. Imam Malik lived in Medina and was Arab by origin. He distinguished himself from other schools of thought by taking the customs of Medina as proof. He took his Fiqh from the scholars of Madinah, who were students of Sahaba.
Maliki madhab spread to northern Africa two centuries later. Think, for example, of countries such as Morocco, Algeria, Tunisia and even parts of Egypt.
Many of the Maliki madhab adherents are Ash'ari and Sufist in creed. That does not stem from the madhab itself. These groups are mainly known in Morocco.
The school of thought of Muhammad ibn Idris Al-Shafi'i (Imam Shafi'i) came right after that of Imam Malik. Imam Shafi'i is a student of Imam Malik, and teacher of Imam Ahmad.
Imam Shafi'i was an Arab and later in life traveled to different areas. He eventually settled in Egypt. He was known for his strong hold on the sources.
Shafi'i madhab is mainly found in Indonesia, Yemen and Egypt. Followers of the Shafi'i madhab are like the Maliki madhab, mainly Ash'ari in creed. This is because of the areas where his madhab is present.
The school of thought of Ahmad ibn Hanbal (Imam Ahmad) came immediately after that of Imam Shafi'i. It thus also makes the last madhab of the last three generations of Islam.
Imam Ahmad came from Baghdad (city in Iraq) and was an Arab who traveled to different areas throughout his life. He had several students he taught including Bukhari, Tirmidhi, Abu Dawud and others.
Hanbali madhab is mainly found in Saudi Arabia, Qatar and Syria. Many of the followers call themselves Salafi in creed.