Miguel José Martins Dantas (1823–1910), secretary of the Portuguese Legation

1st image: Soirée; 2nd: from Receuil: Portraits Famille Royale d'Espagne (1870); 3rd: caricature by Eugène Giraud drawn January 29, 1858 at Nieuwerkerke's soirée; 4th: litho Le Monde Illustré (1890). (Alternative: Muller)

Miguel José Martins Dantas—his name often written in French as d’Antas—held the title of chevalier (Knight). Born in Lisbon into an aristocratic family of military heritage with close ties to Portuguese royalty, his lineage traced back to Agen, Gascony, the birthplace of renowned poet Jacques Boé Jasmin.
Beginning his diplomatic career at eighteen, Dantas was assigned postings in Turin, The Hague, and Vienna before becoming First Secretary of the Portuguese diplomatic mission in Paris from 1848 to 1868, serving under Viscount de Païva02b.
During his years in Paris, Dantas was a highly regarded guest at soirées and imperial gatherings at Compiègne. His popularity was partly fueled by his wit and charm but also, as the gossip press noted, by the high-quality Cuban cigars he always carried. Amusingly, some writers even compared his appearance to the 17th-century Baroque painter Anthony Van Dyck.

A false Dom Sébastien, engraving by Geiger 16th century
A false Dom Sébastien

In 1866, he gained broader recognition with his historical study Portugal, Les faux Don Sébastien (The False Don Sebastians), which chronicled four impostors from the 16th century who falsely claimed to be King Sebastian of Portugal—the blond-haired, blue-eyed monarch who had mysteriously vanished during a 1578 military expedition to Morocco.
Among the pretenders, one was sentenced to the galleys, another was beheaded, a third—a baker—came close to the throne before being imprisoned and later hanged, while the fourth, an adventurer who didn’t even speak Portuguese, met the same fate.
In his book, Dantas refined and expanded earlier accounts of this saga.
Gaetano Donizetti had famously composed an opera on the subject in 1838, using lyrics by Scribe74, and lead role of Dom played by Duprez21.

Dantas’ diplomatic career led him to Washington in 1868, followed by assignments in Brussels, The Hague, and Rio de Janeiro (where he never formally took office), then back to Brussels, London, and Madrid. He returned to Paris in 1890 as head of the embassy, later spending the final chapter of his career as Portugal’s ambassador to the Vatican in Rome.