It is not impossible the fort at Uqair could be the result of the Portuguese domination of the Persian Gulf, which began in 1506 with the expedition of Afonso de Albuquerque. His mission was to destroy Arab trade and establish Portuguese dominance. Their oppressive influence may have completely transformed the regional power structure but they left no religious and hardly any cultural imprint, except for their cannons and ruined garrisons. (From the Trucial States to the United Arab Emirates, Frauke Heard-Bay, p. 271). Before the Portuguese, wealthy city states were developed around favorably situated harbors ... inhabited mostly by Arab tribes ... to dominate the entrepot trade between India, Arab countries and Europe, which passed through Mesopotamia and the Red Sea. (From the Trucial States to the United Arab Emirates, Geoffrey Frauke Heard-Bey, p. 271). The construction of Portuguese forts was common. A large structure still stands on the island of Bahrain (1521 AD) in recognition of its importance as a favorable position to assert their power and control of the Persian Gulf by way of the Straits of Hormuz. (Dilmun Discovered, Michael Rice, p. 70). The Portuguese left the Gulf in 1648 after several revolts of Arab natives attempted to regain their harbors and trade. The confusion and growing interest of the Turks (who also built forts in the region) and Persians created a situation for the Portuguese which they could not control. (The Arabian Peninsula, George Allen, p. 94).