Which former First Lady of the US was the first to be buried at Arlington National Cemetery?

Helen Louise Herron "Nellie" Taft (born June 2, 1861 – died May 22, 1943) was the wife of US President William Howard Taft. She was First Lady of the United States from 1909 to 1913. Nellie was widowed upon the death of her husband on March 8, 1930, and stayed in the city of Washington. She continued to be socially involved serving as an honorary vice president of the Colonial Dames of America and the Girl Scouts of America. She died in Washington, D.C. on May 22, 1943, and was buried next to President Taft at Arlington National Cemetery. She was the first former First Lady of the US to be buried there and created a precedent later used for Jacqueline Kennedy's burial at the cemetery in 1994.