Roots of dismembering of Iran in the past

From the beginning of the 19th century to the Islamic revolution of Iran, the territorial integrity of Iran was violated repeatedly, and every time major world powers separated a part of this vast and ancient land without any proper reaction from the central government.
The first period in which a large part of the territory lost is related to the war of Russia against Iran in the years 1218 to 1228 and 1241 to 1243 AH which led to the breakdown of the Caucasus and Transcaucasia.
The infamous Treaty of Gulistan and Turkamanchay not only lost their stamp of approval on this tragedy, but with the continued commitment and support of the Russian court in the reign of Abbas Mirza generation, gave recognition to Russia clear interference in the internal affairs of the country.
In Naser al-Din Shah Qajar reign in 1273 AH in accordance with the Treaty of Paris and with the machinations of England, Afghanistan, with the aim of countering Russian influence in India and also to establish a security cordon for this important colony of Great Britain, was separated from Iran.
No much passed from this event that once again the Russians entered the field.
It was time to get closer to the Indian border, and become neighbor with China, so, an important part of Central Asia was separated from the stout trunk of this land.
The process of reducing Iran's Geography, based of British strategy in making the size of Islamic countries small and reducing the geopolitical importance of Iran in the Middle East, continued in later periods.
Colonial intrigues to achieve Iranian oil and territorial integrity and also political relations between the major powers led the territorial and political integrity of the country to be abused frequently.
In all these events, incompetent and dependent leaders who owed their existence to the alien could not prevent these assaults.
The most significant of these changes is related to the incident of separation of Bahrain from Iran in 1348 Solar Hijri.
This is followed by the great conflict between Great Britain and Iran on the one hand and the local government of Bahrain on the other hand.
The British clearly announced that Bahrain was somehow dependent on them and this was why they were supporting the separatist tendencies of the sheikhs of there.
In the days of the colonial era
and in the absence of large countries such as India that had lost their independence and while
European powers such as France and Austria were divided, maintaining this same level of the country was of so importance.
But why the loss of a large part of Iran is also interesting
And, more importantly, it can be considered that why the political realm of Iran in the fields of culture and civilization was not established.
And never reached its ancient limits.
In search of answers to these questions we can refer to the following six subjects:

1. The extent of territory of culture and civilization of Iran

Area of culture and civilization of Iran was such extent that it has been very hard for any kingdom to merge all range of Iranian civilization in its political realm.
So, even in the Sassanid era, the political realm of Iran, did not cover all cultural parts of Iran.
For the future of Iran we have to recognize a separation between the political realm and the realm of Persian culture, and in this way we should open the way to unify all limbs of the extensive civilization of Iran.

2. The cultural ruptures

Safavid defence of Shiism and formalization of it retained integrity and independence of Iran. But Uzbek border attacks into eastern and north - eastern Iran, lead to religious gap between residents of east, west and center of Iran. So background was prepared for the final separation of Samarkand and Bukhara from the political realm of Iran.

3. Assault of un-native peoples

With the onslaught of un-native peoples to some border regions and demographic change in these areas, the background was prepared to increase their cultural ruptures, resulting in their separation from the political realm of Iran.
An obvious example of such a situation was the influx of Uzbek and Turkmen to Merv and forced migration of Shiites and Ghezelbashs of this state. This matter caused separation of Merv from the realm of Iran.

4. neighbors military invasion

Repeated violations of some neighbors to the territory of Iran and occupation of border areas caused these regions to be separated from Iran.
Clear example of this situation was occupation of Kurdish Diyarbakir and the Holy Shrines by the Ottoman Empire, and separation of Caucasus because of the failure in the war with Russia which finally led to unwanted separation of these areas from Iran.
These areas from all aspects of culture, civilization and history are integral parts of the territory of Iran.
Russia and the Ottoman invasion was the only cause that these areas were isolated from Iranian territory.

5. foreign intervention

Russia and England were the main elements of separation of Caucasus, Akhal, AbiWord, Herat, Kandahar and Sistan are from Iran.
British colonization also prevented the actions of the government of Iran in British Baluchistan.
And sabotaged in the exercise of sovereignty on the northern coast of the Persian Gulf and its islands. This provided background for separation of Bahrain from Iran.
British colonization also supported the Ottoman Empire in its territorial disputes with Iran.

6. Weakness of the central government

All the five factors mentioned, in light of the weakness of the central government, led to dismembering of Iran.
Lack of a regular and systematic structure, continued wars of succession after the death of kings, internal disputes the clear symbol of which was competition of princes in its internal divisions that compete with each other in the wars with Russia, the central government's poverty especially in the colonial era and the feudal system in Iran all handed to hold the federal government failed to protect properly in the field of water and soil from Iran.
After the Iranian border came about current open space, yet possible threats existed and there was possibility of more separation from Iran. But a new factor came to the fore and protected from Iran's limits against all threats.
This factor was appearance of something called as public opinion and exertion of the nation force.