[citation needed] At the time of his birth, Duarte Pio and the rest of the Miguelist Braganzas were banned from entering Portugal, by the laws of exile of 19 December 1834.

[11] The dispute dates back to 1828 when Duarte Pio's great-grandfather was said to have usurped the throne as King Miguel I, starting the Liberal Wars.

[11][15] In 1912 and 1922, Duarte Pio's grandfather, Miguel Januário, Duke of Braganza, reconciled with King Manuel II, but this reconciliation was not accepted by all of their adherents.

One monarchist group in Portugal that did support Miguel Januário, Duke of Braganza, instead of the deposed King Manuel II was the Integralismo Lusitano.

[17] On 5 July 2006, in response to this statement, Nuno da Câmara Pereira, then leader of the People's Monarchist Party, addressed the President of the Assembly of the Republic, asking for a clarification as to the official recognition of Duarte Pio as pretender to the throne and as Duke of Braganza.

In its official response on 11 July 2006, the Ministry of Parliamentary Affairs restated the fact that the Portuguese constitution guarantees the republican regime[citation needed], and that the reference to Duarte Pio as Duke of Braganza was merely a polite courtesy.

[citation needed] Dom Duarte was a major campaigner for the independence of Timor-Leste, a former Portuguese colony which was forcibly annexed by Indonesia in 1975.

Before the issue's global popularity from the 1990s onward, the Duke contributed with several national and international campaigns for the political self-determination of the territory, including Timor 87 Vamos Ajudar and Lusitânia Expresso.

[18] In February 2012, with final approval and support of Timor-Leste parliament, President Ramos-Horta conferred Timorese citizenship upon Duarte Pio, along with the Order of Merit.

[19][20] President Ramos-Horta stated that these honours were given because of Duarte Pio's "dedication of a large part of his life to defending justice and liberty for the Timorese people.

[citation needed] Duarte Pio told several Portuguese news outlets that it was the Syrian President's intention to "collaborate on the creation of a future constitution for Syria, close to that of Morocco, which guarantees political, religious, and press freedom.

"[24] In his capacity as the President of the King Manuel II Foundation, Duarte Pio is often involved with the Community of Portuguese Language Countries, intergovernmental organization for economic, political, and cultural friendship between Portugal and many of its former colonies.

[25] In 2012, Duarte Pio petitioned, with Maria Hermínia Cabral, Director of the Calouste Gulbenkian Foundation, for their respective organizations to become CPLP consultative observers, to which both succeeded in their endeavor.

[citation needed] In 2014, the Court of Lisbon forbade Duarte Pio of Braganza from using the insignia of the Order of Saint Michael of the Wing and demanded that he compensate 300,000 euros to the legal owner of the rights, Nuno da Câmara Pereira, who allegedly registered the name "Order of Saint Michael of the Wing" in 1981, whereas Duarte Pio is said to have registered it in 2004.

From 24 until 25 May 2009, the Duke visited Terceira Island, in the Azores Autonomous Region, as a guest of honour of the Santa Casa da Misericórdia, for the presentation of Mendo Castro Henriques's book, Dom Duarte e a Democracia – Uma Biografia Portuguesa.

In his speeches, the Duke reflects on the historical significance of the date, events of the previous year, and the road ahead for both Portugal in general and the monarchist cause.

Following her marriage, Isabel de Herédia began a gradual withdrawal from her professional life, a process which was completed by the time her eldest child, Afonso of Braganza, was born.