The Potter family

Before the Potters of course, there is the Peverells: Antioch, Cadmus, and mainly, Ignotus. Ignotus had one son who's name was again, unknown. That son had Iolanthe, who later married Hardwin Potter, a person that had seven unknown siblings and who's parent was known as Linfred of Stinchcombe. Hardwin and Iolanthe had three children. One was unknown, while the other two were Abraham and Ralston Potter. There were many unknown generations that were children and grandchildren of Hardwin and Iolanthe's unknown son. Eventually, we find two children, one, still unknown while the other was Charlus Potter (you might remember that Charlus married Dorea Black). Charlus's brother married some unknown witch and we get to their one and only child, Henry Potter. Henry married a pureblood witch, and they have Harry's grandfather, Fleamont. Fleamont marries Euphimia, and here comes James, Who marries Lily Evans. 
Lily comes from a muggle family and has a muggle sister, Petunia. Petunia marries Vernon Dursley, and gives birth to Dudley, one month before Harry is born.

And you definitely already know that Lily and James have Harry Potter on July thirty-first, nineteen eighty.