document updated 15 years ago, on Apr 7, 2009

The intertwining of church and state has a long history. Politicitions and religious leaders have long recognized that it would have more influence if one side could control the other. Often states created their own local religion, but as religion became more organized, religion started to exert control on the state.

Christianity first grew within the Roman Empire, where it gradually replaced Hellenistic polytheism.
303: the Great Persecution, the last, most severe, episode of persecution of Christians in the Roman Empire
313: Constantine declares that Christianity will be tolerated in the Roman Empire
380: Theodosius I declares Christianity as the official state religion of the Roman Empire
600 -: Christianization of most of Europe
756: the Donation of Pepin creates the Papal States
1056-1122: Gregorian Reform, Investiture Controversy, Concordat of Worms — kings are no longer allowed to choose the pope
1302: Pope Boniface VIII says that "it is absolutely necessary for salvation that every human creature be subject to the Roman Pontiff".
1523: Martin Luther's book, On Secular Authority, suggests that God requires voluntary, not coerced, religious belief
1527 - ?: English Reformation: Oh yeah? I'll see your state church and raise you one of my own!
1789: dechristianisation of France during the French Revolution
1791: United States founded, the first formal separation of church and state
1929: the Lateran Treaty ends the Papal States

Islam first gained power in Persia (Iran), during the time that the Sassanid Empire held power, where it gradually replaced Zurvanite Zoroastrianism.
613-622: Muslims were persecuted at Mecca
622-632: Muhammad migrates to Medina, battles the tribe there, and eventually gains control
630: Muslims conquer Mecca without battle
632: Muhammad dies
632-732: Muslim conquests
- 632-661: Rashidun Caliphate: the first four successors conquer Persia(Iran/Iraq), Syria, Egypt, and parts of the northern coast of Africa
- 661-750: Umayyad Caliphate: conquer all of the north cost of Africa, the Iberian Peninsula, and began pushing towards India
750-1258: Abbasid Caliphate
- 1258: Mongols sack Baghdad
1299-1923: Ottoman Empire
- 1453: Ottomans conquer Constantinople, the capital of the Byzantine Empire

From the very beginning, Muhammad was seen as both a religious and military leader, and as such, church and state are thought to have been united from the very beginning.
622: the Constitution of Medina asserts that dhimmi (non-Muslims) have equal rights alongside Muslims
711-1031: Golden age of Jewish culture in Muslim Iberia
Ottoman millets: formallized the fact that minority religions could have their own separate courts and personal laws
1839-1876: Tanzimat: reforms that replaced the millet system, that intended to give minorities (including non-Muslims) more equal rights within the Ottoman Empire
1923: Mustafa Atatürk helps transform Turkey into a secular state, after which there has been no unifying caliph