Portugal in the Sea of Oman - Religion and Politics is an editorial achievement, which is unique in the Arab World. In cooperation with the Ministry of Religious Affairs of Oman, the University of Aachen and the Arquivo Nacional da Torre do Tombo, the publishing house Philipp von Zabern releases all official documents that have been published during the Portuguese colonial period of the Oman. These documents are historical treasures that allow an undisguised view onto this era. The documents are presented as original scans. During the next years there will also be a transcription into Old Portuguese and a translation into English and Arabic. Thus, the sources become available for scien tist all over the world and a new scholarly dialogue about this essential colonial period can be opened.