How stable was the Middle East under Ottoman rule?

The question is not very clear. But I believe that it intends to ask a comparison of the situation of the Middle East today, where you have lot's of conflicts, wars, disputes; and the reasons behind the same geography peacefully living for centuries under the the Ottoman times. If that's the case, my answer is below.

It is true that Middle East was (relative to the time of it's day), a lot more peaceful during the Ottoman period, compared to last hundred or so years. It is also important to note that there had been serious changes to the definitions of identity and nation during this period.

During the Ottoman period, the empire was a multicultural environment, where there was no absolute domination of a single ethnic or religious group in most of the regions and the cities. The identity was based on religion, not ethnic background, but there was a balance between different religious communities.

Firstly, with the rise of nationalism in Europe after the French Revolution, it didn't take long that ethnic differences started to gain an importance in the daily life in the Ottoman Empire. With the weakening of the Ottoman Empire, external powers (and especially Britain, France and Russia) have started to trigger the minorities of the empire, in order have better influences in the division of what is called the Sick Man of Europe, about to die.

Through these influences, especially the Christian minorities have gained economic and political privileges within the empire, which have later turned into nationalistic movements and ethnic conflicts. Metropolitan cities were shared by multiple ethnic groups, but later on claimed for one.

This has created serious conflicts between many groups and resulted in multiple wars before and after WWI.

Secondly, during the Cold War, the Middle East was positioned on a strategic place just near USSR, and became one of the strongest playgrounds of the rivalry between USSR and the USA. Radical religious movements were used against the communists. Intentionally and externally, conservatism is injected into the societies. But within decades, the radicalism had grown out of control.

Thirdly, once this radical religionism has started to threat the world, especially post 9/11, another external tailoring of the societies took place, which has targeted to divide the ethnic and religious groups. Unfortunately, this has only resulted in the enlargement of the influence of the radicals to all those countries. They were not model democracies before, but most were definitely far away from being extremists.

All these external touches to the Middle East have changed the social dynamics of the countries, in a manner like a mutation causing cancer difficult to fix. Unfortunately, the similar and unsuccessful involvements still take place today.

Middle East was pretty stable compared to today. For instance, Iraq. In Ottoman era there was no Sunni-Shia strife between Arabs. Not even a little bit. After the emergence of Wahhabi Saudis and their Karbala Massacre things began to change. Even in this case Ottoman authorities backed Shia Iraqis against Wahhabi Bedouins.

Another example Syria. In Syria throughout 400 years of Ottoman era there was only one violent interfaith strife. Even in that one Ottoman authorities backed Christians against furious and resented Muslims. After the return of civil order, the pursuit of stolen property and legal charges against those who had injured or stolen from Christians began. Governor of Aleppo issued a decree informing citizens that they had 10 days to return stolen goods, and after that, those found with stolen property would be punished as thieves and rebels.

Lebanon was almost independent. Lebanon was so autonomous that the Ottomans did not care when the ruling Sunni Muslim Shihab family converted to Maronite Christianity. The only thing that the Ottomans cared about was regular taxes and the maintenance of order. It is impossible to even think that such a thing would be possible today.

I don't even need to mention Palestine.

For Kurds, they were also largely autonomous. Until the oppressive Young Turk (perpetrators of Armenian genocide) and Kemalist regime they were never rebelled. When autonomous Kurdish Emir of Botan committed atrocities against Assyrians Ottomans stripped him from his Emirate and exiled him. So yes, compared to today, the Middle East was indisputably stable and better.

The Ottoman Empire was in a state of decline, both internal and external, during the 18th and 19th centuries, accelerating during the latter period, and ending with its total collapse and dissolution during the events surrounding World War I.

Richard Hooker's The Ottomans tell's the story briefly.

Note that by 1800 the Ottoman's had totally lost control of the Barbary Coast and Egypt; European interference in the Lebanon was also disruptive.

The Balkan Wars of the late 19th century were preceded by the successful Greek War of Independence. All of these events signal the weakness of the Ottoman Empire, the "Sick Man of Europe"

The rise of of nationalism in the Ottoman Empire was primarily a 19th century affair; the systematic Ottoman response was the Tanzimat, reform and reogranization that lasted from 1839 to 1878. Many of the reforms were inspired by Western ideas, but failed to accomplish the goals, which were "to bring the benefits of a good administration to the provinces of the Ottoman Empire through new institutions."

Economic stagnation, the refusal to modernize, and the slow loss of territorial integrity means that peace and stability were lacking.

As reported in The Oxford Encyclopedia of the Islamic World:

"Government and Society. The reign of Sultan Süleyman marked the peak of Ottoman power and prosperity as well as the highest development of its governmental, social, and economic systems. The Ottoman sultans preserved the traditional Middle Eastern social division between a small ruling class (askeri or “military”) at the top, whose functions were limited largely to keeping order and securing sufficient financial resources to maintain itself and carry out its role, and a large subject class of rayas (reâyâ, or “protected flock”), organized into autonomous communities according to religion (millets) or economic pursuit (esnaf, or “guilds”) that cared for all aspects of life not controlled by the ruling class."

The article provides details, but even this summary makes it clear that modern theories of police were lacking, and that order was primarily the responsibility of the autonomous communes, with a military presence as a reminder. Thus there are no statistics for criminal activity.

Rebellions in the Ottoman Empire (in Turkey) lists many rebellions, and provides links to the details. The article also provides rebellions by era; the period 1606-1699 is called Stagnation, 1699-1792 is called Decline, and 1792-1922 is called Dissolution.