With the outbreak of a widespread armed conflict between the main European powers in 1914, Portugal was faced with the challenge of maintaining a non-belligerent position, while ensuring sovereignty over its territories.
The Portuguese Navy was responsible for protecting the interests of the State in national waters, in the metropolis and in the colonies, ensuring the defence and surveillance of ports, navigation, and the main maritime communication routes.
Throughout the conflict, and with Portugal's active entry into the war from 1916 onwards, the challenges it faced involved three fields of operations: the Atlantic, the colonies, and the new theatres of war in Europe and Africa. This period was marked by the development of new operational means, both at sea and in the air, which made it possible for the Portuguese Navy to fulfil its missions.
One hundred years later, it is important to preserve the memory of all those who, on land and at sea, intervened and participated in the Great War (1914-1918), some even sacrificing their lives to defend Portugal.