Academics say the discovery goes against the common assumption that all Africans in Roman Britain were low status male slaves.
Remains of the Ivory Bangle Lady, as she has been named, were studied in Reading using forensic techniques.
She was first discovered in the Bootham area of York in August 1901.
Her remains were in a stone coffin near Sycamore Terrace in the city.
Her grave dates back to the second half of the 4th Century. She was buried with items including jet and elephant ivory bracelets, earrings, beads and a blue glass jug.
She also had a rectangular piece of bone, which is thought to have originally been mounted in a wooden box, which was carved to read, “Hail, sister, may you live in God’.
Isotope evidence suggests that up to 20% were probably long distance migrants. Some were African or had African ancestors, including the woman dubbed “the ivory bangle lady”, whose bone analysis shows she was brought up in a warmer climate, and whose skull shape suggests mixed ancestry including black features.
The authors point out that Roman North Africa was noted for its mixed populations, with Phoenician, Berber and Mediterranean influences.
“This skull is particularly interesting, because the stone sarcophagus she was buried in, and the richness of the grave goods, means she was a very wealthy woman, absolutely from the top end of York society,” Eckhardt said.