The Duke of Terceira was a title created in 1851 for the Portuguese nobleman, António de Almeida e Silva. He played a significant role in the history of the Azores, particularly during the Liberal Wars in Portugal. The title is associated with the island of Terceira, which is one of the nine islands in the Azores archipelago. The Duke was known for his military leadership and political influence during a turbulent period in Portuguese history. His contributions helped shape the governance of the Azores and the broader political landscape of Portugal, particularly in relation to the monarchy and liberalism during the 19th century.