AMSTERDAM — Rembrandt’s 1661 painting, “Two African Men,” is one of the Dutch old master’s more inscrutable works. One man, dressed in a Roman-style costume and shawl, seems to be giving a speech, while another man leans attentively over his shoulder. The canvas was painted with a thin layers of earth tones and looks unfinished, but it bears the artist’s signature.

Why did Rembrandt paint it, and who were his subjects?

These were some of the questions that came to mind for Stephanie Archangel in 2015 as she found herself lingering in front of the work at the Mauritshuis Royal Picture Gallery in The Hague.

A sociologist by training, she had been searching in paintings “for black people in which I could recognize myself,” said Ms. Archangel, who was born and raised on Curaçao, an island that was once a Dutch colony. Described by the Mauritshuis’s website as likely showing “free men who lived in Amsterdam,” Rembrandt’s portraits seemed “human and worthy,” Ms. Archangel said.

“It was the first time I saw black people in the 17th century painted by a Dutch master looking proudly back at me,” said Ms. Archangel, who is now a junior curator at the Rijksmuseum. “I was wondering if that was true or not, or if it was my imagination, or just my hope to see that kind of proud representation.”