Nadezhda Yakovlevna Mandelstam has a recollection of how she and her husband chanced upon namesakes in a watchmaker's workshop in Yalta

Nadezhda Yakovlevna Mandelstam has a recollection of how she and her husband chanced upon namesakes in a watchmaker's workshop in Yalta. While writing out a receipt, the watchmaker was stunned to hear his own surname from his customers. He invited the Mandelstams to his home and told them that he kept a detailed family tree of their line, from which he had established beyond doubt the degree of kinship between them.

"...he gasped on hearing the surname and ran to fetch his wife. It turned out that she, too, was a Mandelstam, and the family is considered a 'yichus', that is, a noble rabbinical lineage. . The old woman could not in any way get out of Mandelstam the particulars of the branch from which he had come. Mandelstam did not even know his grandfather's patronymic. The old people invited us into the room behind the shop and pulled out of a chest a large sheet with a carefully drawn genealogical tree. We found everyone on it: the translator of the Bible, a Kyiv doctor, a physicist, the Leningrad doctors, the watchmaker's wife, and even the grandfather and his father. There turned out to be a terrible number of Mandelstams, far more than we had thought."

The archaeologist Anatoly Mandelstam, his father and his uncle, all well-known physicians, also come from the extensive clan of the Mandelstams.