Whatever the definition of “ethnicity”, it does not fit comfortably into any of the present or past political boundaries of modern countries. 

Here is some food for thought.

• James Tanner, “DNA, Genealogy, and Political Entities“, Genealogy’s Star (Sept. 19, 2019). Retrieved Oct. 16, 2019.
• James Tanner, “What is Ethnicity and Why Do We Care?“, Genealogy’s Star (June 28, 2019). Retrieved Nov. 9, 2019.

Updated to add link.