State Instability in Iran (3000 BC to 1600 AD) as Part of Central Asian Interactions with other Regions of Eurasia

Background and ContextNumerous studies have indicated that the state instability existence in past of countries has not only delayed their development but also influenced their current level of development. The study of political instability in the Eurasian region during the agricultural era (3000 BC to 1600 AD) encompasses a significant portion of the history and the contemporary world geography. It can serve as a basis for examining political instability in the history of Iran. Many scholars have considered the proximity to the Central Asian nomadic societies as one of the factors contributing to instability in Eurasian countries. Some of them argue that the history of these tribes' interactions with neighboring regions forms the core of Eurasian history. There are also a limited number of quantitative studies that have encompassed various aspects of these tribes impacts on neighboring communities. There have been numerous studies on the effects of these tribes on Iran as well, but none of them have covered this temporal and geographical scope.Objective of the ResearchThe main objective of this research is to investigate political instability in Eurasia, particularly in Iran, during the agricultural era. It focuses on the Central Asian nomadic influence tribes on the creation of political instability in Eurasia. The research utilizes this framework of interactions and gathered information to periodize political instability in the history of Iran.Research MethodologyIn this study, political instability is perceived as a low average lifespan of states and a high coefficient of variations (standard deviation-to-mean ratio). The study considers Continental Eurasia (including Europe and Asia, excluding their islands) as the studied region and the agricultural era 3000 BC to 1600 AD as the studied period. To assess the timing and extent of Central Asian tribes' influence on political instability in Eurasian states, a total of 432 Eurasian states in the study period were identified. Subsequently, the time and extent of Central Asian tribes' impact on political instability were examined by applying three categorizations to these states: 1) Regional categorization based on the importance of the region each government could have for Central Asian tribes, dividing into Central Asia, unimportant region, less important region, and highly important region. 2) Since the period of significant influence of these tribes on Eurasian developments occurred between 500 BC and 1600 AD, states that existed before 500 BC were classified as belonging to the first period, while others belonged to the second period. 3) By combining the previous two categorizations, the states were grouped into four categories: (I)Central Asian states, (II)unattractive states, (III)low unattractive states, and (IV) highly unattractive states.Descriptive analysis, Two-sample Kolmogorov–Smirnov test (KS2), and categorical regression were used for data analysis and inference.FindingsThe findings regarding regional categorization show the significant differences in the lifespan of states among regions. The average lifespan of states in unimportant regions is more than 3.5 times that of highly important regions, and the coefficient of variation for highly important regions is higher than for other regions. Regression results confirm the model and regression coefficients validity, indicating that this four-group categorization explains 29% of the variations among states.Statistical analysis demonstrates a significant difference in the mean lifespan of states between these two periods. Specifically, the average lifespan of states in the first period in the Region Two, a significant region, is nearly eight times higher than the states in second period of that region. Additionally, the lifespan of states, particularly in Iran, has decreased during the agricultural era.These analyses also reveal significant differences in the average lifespan of states within the categorized groups, with coefficient determination of 0.429. The mentioned item indicates that this model accounts for a significant portion of the variations in the lifespan of the examined states.Moreover, Iran's status in terms of the number, average lifespan, and coefficient of variation of states is examined within different groupings, and the KS2 test confirms that Iran's belonging to specific groups and the irconcordance lack of other groups, except for its concordance with Central Asia.Several supplementary studies on Chinese history, the timing of the beginning and end of the agricultural era, and the period of Central Asian tribes' influence provide further support for the stability of the results.ConclusionThe statistical analysis results show an inverse relationship between the average states lifespan and the level of threat from Central Asia in various categories of states. Evidently, the agricultural-era states' political instability was significantly affected by the invasions of Central Asian tribes. The four-group categorization explains approximately 43% of the variation in states’ lifespans. Notably, this level of explanation is achieved with only four categorical variables.Regarding Iran, the findings indicate that the political instability of Iranian agricultural-era states was also influenced by interactions with Central Asian tribes. The periodization of Iranian history can be established as mentioned bellow:(up to 600), (600 to 1000), (1000 to 1250), and (1250 onwards), with distinct events in the second period onwards attributed to Central Asian tribes, such as the emergence of the Seljuks and the Mongol invasions. The results demonstrate that political instability in Iran was higher than the average for other regions, with an average government lifespan of 90 years during the fourth period, which lasted for approximately 550 years, slightly exceeding the average lifespan of a human today.