I don't really think they have real names. They are just fill-ins for nameless victims or demonstrations.
plaintiffs in roe vs. wade These are not their real names. John & Jane [ or Mary Doe ] are used to protect people's privacy , and are often used when real names are not wishing to be disclosed.
icomposer real Mary
John and Mary Grayson
their names were elizabeth Mary and esther
Mary Khavere
William Shakespeare's parents names are Mary and John Shakespeare
If the names are like, "John Smith -and- Mary Smith", then they both have to sign the title. If the names are like, "John Smith -or- Mary Smith", then one signature is needed, and it can be by either one.
He was the son of the Reverend John Hancock and Mary Hawke Thaxter
John Steinbeck had three sister, Mary, Beth and Esther.
His mother Mary and John his disciple
John Shakespeare and Mary Arden were his parents.
John Shakespeare, an alderman - and Mary Arden