This large natural harbour on the east coast of the northern Emirates has been an important site of maritime trade and settlement since the pre-Islamic era. There is some slight evidence, mainly from tombs, of settlement during the later 2nd millennium and the early first millennium BC, contemporary with such sites as Shimal, Tell Abraq and Rumeilah. There is also scattered occupation during the period of al-Dur and Mileiha but it is in the period just prior to, and after, the coming of Islam that we hear most about Dibba. Under theSasanians, and their Omani clients the Al-Julanda, an important market existed at Dibba and that it was sometimes the capital of Oman. According to Ibn Habib "merchants fromSindh, India, China, people of the East and West came to it."
Soon after the death of the prophet Muhammad a rebellion broke out at Dibba and a faction of the Azd, led by Laqit bin Malik Dhu at-Taj, rejected Islam. According to one tradition Laqit was killed by an envoy of the caliph Abu Bakr in what may have been a relatively small struggle, while other sources including Al-Tabari say that at least 10,000 rebels were killed in one of the biggest battles of the Ridda wars. The plain behind Dibba still contains a large cemetery which according to local tradition represents the fallen apostates of Dibba.
During the time of the Abbasid caliph Al-Mu'tadid (AD 870–892) a great battle was fought at Dibba during the conquest of Oman by the Abbasid governor of Iraq and Bahrain,Muhammad bin Nur. Thereafter references to Dibba in historical literature are scarce, until we come to the Portuguese who built a fortress there. Dibba (Debe) appears in the list of southeast Arabian placenames preserved by the Venetian jeweler Gasparo Balbi in AD 1580 and depictions of its Portuguese fort can be found in several sources, such as Cortesao's Portugalliae monumenta cartographica.
Around 1620–1621 the Italian traveller Pietro Della Valle, while staying with the
