One of the criteria by which states in the current international system can be classified is the amount of power they actually enjoy or are often thought to have. Based on this criterion, states are divided into big powers, middle powers and small states.
Great powers are states that define global interests and responsibilities for themselves, they mainly play a leading role in international organizations, they act unilaterally in the first place, and in case of failure, they act in cooperation with other counterparts, an unequal/one-sided relationship. They establish relations with other states, including middle powers and small states, and in addition, in a socio-historical context, their status as a great power has been recognized by other members of the international community.
The middle powers neither have the capacity nor the desire to become a great power, nor are they weak enough to be caught in the abyss of absolute action. Instead, their ability in the international arena is average, by not challenging the existing international system and its great powers, they advance their foreign policy based on domestic prosperity and survival in the international arena, and by creating norms of peaceful behavior. and encouraging the settlement of disputes through international law and international institutions, instead of resorting to force, they try to introduce themselves as a country that seeks to stabilize the world order.
Small states, meanwhile, have some distinctive features: for example, they have to adopt one of two approaches towards international developments not least international conflicts: diplomatic Isolationism or diplomatic activism. Thus, the limitation of internal power resources as well as foreign power relations makes the small state to adopt a cooperative approach, which, as a result, makes mediation the Centre of its diplomatic efforts. 
However, in today's era, small states are not like in the past that cannot compensate for their vulnerability because they have increasingly become important and influential actors in international politics. Although the scale of their operations is significantly different from that of larger states, they are not ignored even in the current world of unequal power relations, so that their diplomatic activities and influence on international politics may exceed their actual capabilities.
The Sultanate of Oman is a clear example of a small state that has become an influential state, at least at the regional level, by adopting a policy of mediation in its foreign policy. Since the reign of Sultan Qaboos bin Saeed (1970-1920) and even following his death, this state has adopted a distinct foreign policy based on mediation. On this basis, the question of the present study is why mediation has played a pivotal role in Oman's foreign policy in the face of regional developments in West Asia during the reign of Sultan Qaboos. In answering to this question, drawing on the conceptual framework of the small state Diplomacy, and Using the integrated method of quantitative-qualitative content analysis, it is argued that the limitations of Oman's power as a small state have made Oman willing to mediate in foreign policy in the face of regional developments in West Asia. The findings of the study indicate that the opportunities of Oman's foreign policy for the Islamic Republic of Iran far more than its challenges, so that this sultanate can reduce the current regional and international pressures and moderate the behavior of enemies and rivals of the country.
In this article, it was shown how Mbanjigari has been able to promote a small state like Oman as a respectable actor in the international and regional arena. In this regard, by turning to a functional explanation, it was argued that the centrality of mediation in diplomatic efforts, with its "branding/highlighting function", was caused by Oman's cooperative approach towards regional and international actors and issues; And Oman's cooperative approach, with its "function of ensuring survival", has arisen from the limitations of Oman's power and has caused this government to adopt a cooperative approach in order to compensate for the damage caused by it, and as a result, mediation is the focus of its efforts. Having said that, Oman as a small state has always acted as an adopted child of great powers. In continuation of this tension-free approach with great powers, Oman has tried to use communication mediation to highlight itself.