I chose to make the obscure historical character Vicente de Rocamora, 1601-1684, as the MC for my Historical novel, ROCAMORA, set in 17th century Spain and Amsterdam, because of the challenge. It was the nearest thing to playing detective.
Based on my research, no book, no monograph, not even an article in any historical journal exist that that describes his life. Vicente is mentioned in assorted books on the Jews who left Spain and Portugal in sentences, a paragraph or two at most, and in both the Valencian and Jewish encyclopledias.
What has been written about Vicente piqued my curiosity many decades ago, and I let the idea for a novel gestate slowly until 1990 when I began serious resarch without the Internet to help.
Here is what piqued my interest in him.
He was born in Valencia, which is ambiguous because it is either the city of Valencia or somewhere in the Kingdom of Valencia.
Sources say he was born into a new-Christian family (Jews forcibly converted), but there is no proof of that.
He entered the Dominican Order, which would have been typically at the age of sixteen -- no source says why.
He went to the College of Confessors of Santo Domingo in the southern most area of Valencia where my research discovered lived the caballero class of significant de Rocamoras who owned the senorios of Rafal, Benferri, and Granja de Rocamora, knights of Santiago, and military heroes descended from Kings of France.
Somehow, Vicente ended up in Madrid. No sources explain how or why. And soon he became the confessor for the teenage sister of Philip IV, Infanta Maria, only five years younger than he in the era before confessional booths. For that he would have need a certificate of limpieza de sangre, purity of blood untained by Jew, Moor, or recent convert.
Sources say Maria confessed regularly, honored Vicente, and showered him with gifts. The same sources say that she remembered him fondly after she became wife of the future Holy Roman Emperor.
Sources also say Vicente was renowned for his piety and eloquence and was a fashionable confessor.
Then, in 1643, Vicente disappeared from Court, reappeared in Amsterdam, declared himself to be a Jew, and took the name Isaac Israel de Rocamora. There is more, but that would be the spoiler where I end the novel.
There is no evidence Rocamora Judaized in Spain, and there is no evidence he was denounced to the Inquisition. He left when the most powerful man in Spain, Count-Duke de Olivares, fell from power, and the relatively benign Inquisitor General Sotomayor, so one may assume it was for political rather than religious reasons.
And as it happened, from 1643-47, he did not identify with the Sephardic community. He went to medical school, received his license to practice in 1647, married a twenty-five year old, and sired nine children over the next eleven years.
Other obscure characters worth a novel in my opinion are:
Daddy Dan Rice, was Barnum's competitor, who cheered Lincoln in the White House with his jokes, supposedly created the Uncle Sam Costume, and whom Jesse James refused to rob on a train because he had been entertained at his circus.
Bodo, the Apostate, whom I mention in ROCAMORA is another. Born a into a pagan Germanic noble family forcibly converted by Charlemagne, he became a Deacon at the court of Louis the Pious/Debonair and the king's favorite. At age 35, Bodo went on a supposed mission to Rome but instead headed south to Spain where he converted to Judaism, submitted to circumcision, and took a Jewish woman as his wife. Then he donned armor, went to Cordoba, fought and polemicized against Christians.
I suppose resarching one about whom so little has been written is the mirror opposite of doing the same for well plowed turf such as the Tudors and Plantagenets.
I have had a wonderful time having my instincts proven right and the thrill of uncovering historical material not published previously.