Dr. Armistead Peter was one of George Peter’s sons from his third marriage to Sarah Norfleet Freeland Peter. He was born on February 23, 1840. Dr. Armistead Peter was a cousin to his wife Martha Custis Kennon Peter, whom he married in 1867. Together, Martha and Armistead had five children: Walter Gibson, Armistead, Beverley Kennon, George Freeland, and Agnes. He and Martha Custis Kennon Peter both moved into Tudor Place and Dr. Armistead Peter converted a portion of the house for his medical practice. He created a very successful business as one of the best doctors in the city of Washington. During the Civil War he was employed by the U.S. Army as ward surgeon, as well as serving in a smallpox hospital. Martha Custis Kennon Peter died suddenly in 1886. Armistead died in 1902, his mother-in-law, Britannia W. Peter Kennon outliving both of them. The land in Bethesda was divided between their four children. After Britannia W. Peter Kennon died, the house was left to her grandson, Armistead Peter II. Dr. Armistead Peter died on January 28, 1902.