I am a member of Ancestry.com, and I tested my DNA there. As a result, I found that I have a blood relationship with a person called John Holme. He was born in Croston, Lancashire in 1754. His father was Richard Holmes.
I examined my great grandfather in Japan and found a candidate. His name is Cecil Zohrab Ede. His mother's name is Helen Ede. Her maiden name is Helen Holme. She was born in Strand, Lancashire in 1835. Her father is Thomas Holme.
If Thomas Holme and Richard Holmes share a blood relationship, I think that I would be able to conclude that my great-grandfather was Cecil Zohrab Ede. However, I cannot find any historical documents showing that relationship.
How can I determine the relationship between Thomas Holme and Richard Holmes?