Since the end of ancient era, the Nestorian diaspora took shelter in Kharg Island alongside the native Zoroastrians, who were engaged in trade as well as religious preaching.
Qaramata, as a sect opposed to the Abbasid caliphs, took refuge on the shores of the Persian Gulf from Jannabah (Ganaweh) and Kharg to Bahrain and formed a government that penetrated as far as Shamat and Hijaz.
On the other hand, Kharg was the famous Kharki pearl extraction site.
We can talk about the emergence of pearl merchants in Kharg Island and Bahrain, and because of the centrality of Bahrain, economy of Kharg also prospered; Especially since pearls have been one of the most important trade goods of Bahrain with the East.
The aim, is the comparative study of the commercial and cultural life of Kharg Island in the transition from the ancient discourse to the developments of the Islamic period.
 The present article, with descriptive and analytical research method, follows the comparative study of the role of Nestorians and Qaramata in trade and shipping in Kharg Island.
The findings of the research show that the mastery of the dangerous sea routes in the passage of Kharg Island and especially the management and productivity of the pearl mines of Kharg Island has strengthened the commercial network and the political independence of the local communities there, including Nestorian and then Qaramatians. The innovation of the present article is that the above events connected the Kharg Island to the pearl sea trade in three layers, local, regional and global, and in addition to economic self-sufficiency, it helped the political independence of the Nestorian diaspora, and then more or less matching in the history of Qaramata.