Introduction
In today's world, businesses face many challenges and changes, and brand, as one of the few organizational resources, can provide them with a long-term competitive advantage. In today's era, the brand offers convenience, trust, identity, ease and prestige to the customers and in return, it receives from them a desire to buy. In fact, a brand is a seller's permanent commitment to provide certain features, benefits and services to buyers. Examining world famous companies and brands shows that many of them have a significant lifespan; As Hodson's (۲۰۰۷) studies showed that among the top hundred global brands, more than a quarter of them have existed since the ۱۹th century. This shows that important brands have more life than several human generations and some of them are very old. This feature allows brands to succeed in the market and provides multiple benefits to both brands and consumers. As one of the intangible and valuable assets of the organization, brand heritage plays a key role in creating differentiation, strengthening brand identity and increasing customer loyalty. But a look at Iranian businesses and brands shows that instability and short life are recurring phenomena. Among them, it is an issue that has deprived many Iranian brands of enjoying and benefiting from brand heritage and has created a phenomenon that is discussed in this article. It has been referred to as a "disruption of brand heritage". The current research was carried out with the aim of identifying, analyzing and leveling the factors affecting "disruption of brand heritage".
Methodology
In order to achieve this goal, the Interpretive Structural Modeling (ISM) method was used, which is known as a powerful tool for analyzing complex relationships between different factors. Factors affecting the "disruption of brand heritage" have been extracted by studying the history of ۴۲ Iranian brands and the final factors have been categorized and entered into the model in the form of ۱۱ influential and influential factors on the disintegration of the heritage. The identified variables are placed in ۴ levels based on the power of influence and dependence. In order to confirm the model, the help of Mic Mac analysis was also used.
 Results and Discussion
According to the ۱۱ factors identified and using the opinion of experts, a four-level model was developed. In this model, "instability of society" was placed as the most important factor at a higher level, which shows that the instability of society and extensive changes in Iranian society play a key role in the phenomenon of breaking brand heritage. In other words, the stability and sustainability of the society is a necessary prerequisite to deal with the break of the brand's heritage. The results of this research show that factors such as "change in symbols", "longevity", "fundamental values", "brand nature", "illegal restrictions imposed on managers", "intensification of competition", "weak management" and "accidents" ", they all affect the phenomenon of brand heritage discontinuity. However, what provides the basis for the emergence of these factors is social instability, which itself leads to "instability in laws and policies" and "illegal actions" among companies. Therefore, social security and stability can be considered as one of the critical inputs for the sustainability of brands, which governments and society are considered as valuable sources of these inputs.
Conclusion
Based on the evidence and model presented in this research, it can be concluded that creating stability and stability in the society is the basic solution to overcome the instability of Iranian brands. This goal is achieved through strengthening the rule of law, increasing government accountability to the people, and supporting the private sector. Of course, creating stability and stability in society is a long and difficult path. Therefore, in the short term, economic enterprises can take measures to protect themselves and their brands from the negative effects of social instability. The study of Iranian brands in this research showed that some brands with strategies such as "continuous monitoring of social conditions", "conscious reactions to complications caused by social instability", "participation and cooperation with other companies to control instability", and "management of relations with the government" ", have been able to somewhat resist the damage caused by an unstable and unstable society. The results of this research remind the importance of stability in the society as a key element in the sustainability of brands, and on the one hand, it can help the policy makers of the society in strengthening Iranian businesses, and on the other hand, it can help to improve branding strategies and strengthen brand heritage in Iranian companies. and finally, ensure the stability and long-term success of Iranian brands in the domestic and international markets.