Abstract: Concepts have been interpreted differently by historians in different times to give a comprehensive view of the past. We are familiar with political history, social history, economic history and administrative history. Maritime history or Sea Power history is yet another concept, which has been gaining momentum and currency these days. Maritime history has become a tool in the hands of several Indian historians who are interested in Indo- Portuguese history. The study of maritime history enables to come closer to the crucial dynamics of historical process. Maritime history embraces many aspects of history, such as international politics, navigation, oceanic currents, maritime transportation, coastal society, development of ports and port-towns, sea-borne trade and commerce, port-hinterland relations and so on. As far as India and the Indian Ocean regions are concerned, maritime studies have a great relevance in the exchange of culture, establishment of political power, the dynamics of society, trade and commerce and religion of these areas.