Arnaud distinguished himself as a geographer, ethnologist, and linguist, gaining intimate knowledge of Abyssinian polemarchs and serving as an active observer of their battles and courtly life.

In 1868, Arnaud published the seminal account of their travels, titled Douze ans de séjour dans la Haute-Ethiopie [fr], providing a comprehensive narrative of their twelve-year sojourn in the region.

Arnaud's father, Michel Arnauld d'Abbadie (1772–1832), hailed from an ancient family of lay abbots in Arrast, a commune in the canton of Mauléon.

In 1791, to escape the repercussions of the French Revolution, Michel emigrated, first to Spain and later to England and Ireland, where he became a shipowner, specializing in the importation of Spanish wines.

At the age of seventeen, Arnaud d’Abbadie was intrigued by Freemasonry after hearing his friends describe it as a benevolent society devoted to philanthropy.

A fervent patriot, though French by marriage, she was the last direct descendant of the Thomson of Park family and could not bear the thought of her son pursuing a path that might one day require him to take up arms against England.

To steer him away from such aspirations, she sent Arnaud to his ancestral homeland in the Basque Country, where exile had only briefly interrupted the enduring legacy of his lineage.

Even if you do not fall for France, you will nonetheless serve your country, for you will have the opportunity to gather the instructive and valuable insights that a true observer gleans from the field of action.” The young man endeavored to follow his friend’s plan.

Aware of his elder brother’s intention to explore Abyssinia, he decided to join the expedition, driven by the shared ambition of locating the sources of the Nile.

Adding to these hardships were the suspicions of colonial powers, as the British, Italians, Germans, and Turks all suspected the d’Abbadie brothers of engaging in espionage under the guise of scientific exploration.

Arnaud, an ethnologist, focused on studying the diverse peoples he encountered, meticulously documenting their cultures, customs, and ways of life.

Their keen observations on ethnology, linguistics, and politics became invaluable contributions to the understanding of a region that had long eluded European comprehension.

Adopting the persona of an Ethiopian scholar, or memhir, he dressed in traditional attire and walked barefoot, as sandals were reserved for lepers and Jews.

Once these relationships were secured, Antoine worked discreetly, gathering crucial information on Ethiopia’s geography, geology, archaeology, and natural history.

[10] Arnaud returned to France with a clear objective: the realization of his ambitious project to reconstruct the ancient Christian empire of Ethiopia, with Dejazmach Goshu as its leader.

However, honoring a request from his mother, Arnaud pledged not to cross the Tekezé River—a tributary of the Black Nile located along the western border of Tigray—so that he could maintain an accessible route to the sea for his return to France.

In November 1852, the Battle of Gur Amba marked a pivotal moment, ending with the death of Dejazmach Goshu and the triumph of Kassa Hailu, who would later ascend to power as Emperor Tewodros II.

The British had established a formidable presence in Sudan, Aden, and Somalia, heightening the likelihood of a confrontation with Emperor Tewodros II of Ethiopia.

Recognizing the strategic importance of Ethiopia, Arnaud sought an audience with Napoleon III to advocate for French involvement.

Although Napoleon III received Arnaud courteously and listened attentively, he ultimately declined to take action, citing France’s obligations under existing alliances with England.

They had nine children:[11] In Paris, Arnaud hosted a salon at his residence on the rue de Grenelle, which became a regular meeting place for intellectual and educated individuals.

The memory of "Ras Mikael" remained alive in Ethiopia for a long time, indeed Emperor Menelik II referred to him: […] "He had, in his person, made to love the France.