Son of Robert B Biddle (b. November 1856) and Joanna Elizabeth Byers (b abt 1856 d after December 1897 and before 1900). His parents married on February 7, 1875. The June 25, 1880 census of Vail's, Pickens County, Alabama states he was only eight months old at the time and it shows that he was born in September. So his birth date would have been September 1879. The birth year of 1872 on his monument is not correct.

William N. Biddle in the 1880 United States Federal Census
Name: William N. Biddle
Age: 8/12
Birth Date: Sep Abt 1879
Birthplace: Alabama
Home in 1880: Vails, Pickens, Alabama, USA
Dwelling Number: 202
Race: White
Gender: Male
Relation to Head of House: Son
Marital Status: Single
Father's Name: J. R. Biddle
Father's Birthplace: Alabama
Mother's Name: Joann Biddle
Mother's Birthplace: Alabama
Household Members Age Relationship
J. R. Biddle 23 Self (Head)
Joann Biddle 20 Wife
Minia C. Biddle 4 Daughter [Minnie]
William N. Biddle 8/12 Son

Joanna was the first wife of Robert B. Biddle. I haven't been able to find the burial place of Robert B. and Joanna Elizabeth. I would guess it was either in Millport, Lamar County, Alabama or Pickens County, Alabama.

Robert B. and Joanna Elizabeth had the following children:
Minnie [married name Todd] b. November 17, 1875; See Find-a-Grave Memorial 39843489
William "Nelson" b. Sep 25 1879; birth date on his monument is incorrect. It states 1872.
See Find-a-Grave Memorial 76941471
John Lee b. April 14, 1887; See Find-a-Grave Memorial 126669928.
Mary B [married name Netherlain] b. April 1889. See Find-a-Grave Memorial 76811125
Dollie [married name Self]. b. February 14, 1892. See Find-a-Grave Memorial 41189368.
Lena [married name Dutton) b. December 1897. See Find-a-Grave Memorial 67949689.

Robert B. Biddle married again after Joanna Elizabeth Byers Biddle died. On March 13, 1900 in Lamar County, Alabama, he married Permelia Malissa Shaw Hydrick (1873 - 1931; Find-a-Grave Memorial 121666090). Robert and Malissa had one child together. Her name was Lula Biddle (b. Oct 28, 1900) who married David Alexander Cash. See Memorial 155024991.

After Robert B. Biddle died, Melissa married James Elbert Hydrick. The children of James Elbert Hydrick and Permelia Malissa Shaw were as follows:
(1) Maggie Lee Hydrick [married name Stripling]. b. 9 June 1906. See FAG Memorial 33853697.
(2) Lillian Mozelle Hydrick [ married name Estes]. b. 15 June 1912. See FAG Memorial 5599493.