In his first homily, the pope emphasizes the missionary work ‘desperately needed’.

The grandparents, Joseph Martinez and Louise Baquié, eventually moved to Chicago in the early 20th century and had a daughter: Mildred Martinez, the mother of the Pope.

The discovery means that Leo XIV, as the pope is known, will not only break the ground as the first Pope born in the US. He also comes from a family that reflects the many threads that are part of the complicated and rich tissue of the American story.

The Pope’s background was dug up on Thursday by a genealogist in New Orleans, Jari C. Honora, and confirmed to the New York Times by the older brother of the Pope, John Prevost, 71, who lives in the suburbs of Chicago.

“This discovery is just an extra memory of how we are intertwined as Americans,” said Mr. Honora at the end of Thursday in an SMS message. “I hope it will emphasize the long history of Black Catholics, both free and slaved, in this country, including the family of the Holy Father.”

It is unclear whether the new pope once tackled his Creole descent in public, and his brother said that the family did not identify as black. The announcement of his election in Rome was aimed at his early life in Chicago and decades of service in Peru.

Mr. Honora, who works in the historic New Orleans collection, a museum in the French neighborhood, began to investigate the background of the Pope because of his French-sounding name, Prevost, but quickly found connections with the south.

His trail of evidence that connects Leo with New Orleans includes the marriage certificate of the grandparents of their seventh district wedding in 1887, a photo of the Martinez Family Grave Marker in Chicago, and an electronic birth record of Mildred Martinez that shows that she was born in Chicago in 1912.

The birth record mentions Joseph Martinez and “Louis Baquiex” as parents of Mildred. The birthplace of the father is mentioned as the Dominican Republic; The mother, New Orleans.

Mr. Honora also found records from the 1900 census that Mr Martinez mentioned as ‘Black’, his birthplace as ‘Hayti’ and his occupation as ‘cigar maker’. The details of Mr. Martinez appear on the sixth line of a page of the census that Mr. Honora with The Times shared.

“Both Joseph Norval Martinez and Louise Baquié were people of color, no doubt about it,” said Mr. Honora.

The exact birthplace of Joseph Martinez remains a bit of a mystery – Mr. Honora also found a census record from 1870 that says that the pope’s grandfather was born in Louisiana. But he said it was not uncommon for people to change their answers to official data.

Joseph Martinez and Louise Baquié married in our Lady of the Sacred Heart in New Orleans. Until it was destroyed by a hurricane in 1915, the church building in Annette Street was a historic center of Afro-Creole Culture in the seventh department of the city.

Creoles, also known as ‘Creole people of color’, have a history that is almost as old as Louisiana. Although the word creole can refer to people of European descent born in America, it usually describes people of color -mixed breed.

Many Louisiana Creolen were known in the 18th and 19th centuries as “Gens de Couleur Libres” or free people of color. Many were well trained, French-speaking and Roman Catholic.

In the course of the decades they established a foot in the business world, the building trade and the art, in particular music, with important contributions to the development of jazz. They remain an important strict in the famous heterogeneous culture of the city.

The revelation of the heritage of the new Pope is a great moment for the history of Louisiana Creolen, said Lolita Villavasso Cherrie, a co-founder at Mr. Honora or The Creole Genealogical and Historical Association.

“I hate to say it, but we feel, many of us that our history was hidden from us,” said Mrs. Villavasso Cherrie, 79, a retired teacher. Partly, she said, because many creoles have been ‘successful’ over the years as white.

It was only with the arrival of the internet, she said that many people started investigating their family history and became aware of their Creole roots. She noted that a considerable number of Louisiana Creolen to the Chicago In the 20th century.

John Prevost, the pope’s brother, said that their father’s grandparents came from France and that his father was born in the United States. He said he and his brothers did not discuss their Creole roots.

“It was never a problem,” said John Prevost.

What all this means, when it comes to the racial identity of the pope, affects some of the national questions in American society, but also reflects the rich diversity of American experience.

“We are all only a few degrees (or less than a few degrees) away from each other,” said Mr. Honora, the genealogist.

Julie Bosman Contribute to report from Chicago. Susan C. Beachy contributed research.