320 Commonwealth was designed by architect Samuel D. Kelley and built in 1881-1882 by Antoine Xavier and William Welch, builders, for building contractor John W. Shapleigh, probably for speculative sale, one of two contiguous houses (318-320 Commonwealth). John Shapleigh is shown as the owner on the original building permit application for the two houses, dated September 6, 1881, and as the owner of 320 Commonwealth on the 1883 Bromley map.
By the 1883-1884 winter season, 320 Commonwealth was the home of Edward Augustus Taft and his wife, Adelaide (Larrabee) Taft. They previously had lived at 29 Chestnut. Adelaide Taft is shown as the owner of 320 Commonwealth on the 1888, 1890, and 1898 Bromley maps, and was the assessed owner through 1904.
Edward Taft was owner of the New York and Boston Despatch Express Company.
They continued to live there in 1896, but by 1897 had made their primary residence in Bourne.
By the 1896-1897 winter season, 320 Commonwealth was the home of Joseph W. Merrill and his children. A widower, he was a retired wool merchant from Exeter, New Hampshire. They continued to live at 320 Commonwealth until mid-1900, when they moved to the Hotel Vendôme.
During the 1903-1904 winter season, the Tafts were living elsewhere and 320 Commonwealth was the home of Philip Shelton Sears and his wife Mary Cabot (Higginson) Sears. He was a lawyer and trustee, and later would become a noted sculptor. They previously had lived at 4 Gloucester. By 1905, they had moved to 184 Marlborough.
320 Commonwealth was not listed in the 1905 Blue Book.
The Tafts probably resumed living at 320 Commonwealth in early 1905, but moved that year to New York City.
By mid-1905, 320 Commonwealth was the home of Joseph Francis Howland and his wife, Helen Taylor (Delano) Howland. They previously had lived in Dorchester. Helen Howland was the assessed owner of 320 Commonwealth in 1905, and Joseph Howland was the assessed owner from 1906 through 1914 and is shown as the owner on the 1908 Bromley map. They also maintained a home in South Paris, Maine.
He died in July of 1914. Helen Howland continued to live at 320 Commonwealth until her death in May of 1915.
In mid-1915, Dr. George Phippen Sanborn, a physician, and his wife, Adalyn (Henderson) Sanborn, purchased 320 Commonwealth from the estate of J. Frank Howland. The transaction was reported in the Boston Globe on June 30, 1915. However, J. Frank Howland’s Heirs continued to be the assessed owners through 1919 and are are shown as the owners on the 1917 Bromley map. Adalyn H. Sanborn was the assessed owner from 1920 through 1940 and is shown as the owner on the 1928 and 1938 Bromley maps.
By the 1915-1916 winter season, the Sanborns had made 320 Commonwealth their home. He also maintained his medical office there. They previously had lived in Brookline and he had maintained his office at 366 Commonwealth. In about 1930, he moved his office to 412 Beacon, and by 1931 they were living in Cambridge.
By 1931, 320 Commonwealth was the home of Mrs. Lula (Fox) M. Darling, the former wife of Jerome M. Darling, who leased it from the Sanborns and operated it as a lodging house. She previously had lived at 337 Commonwealth, where she also had operated a lodging house.
In December of 1931, the Building Department cited Adalyn Sanborn for failing to provide sufficient egress. It appears she failed to remedy the violation, and she reminded by letter in February of 1932, of the requirement.
Mrs. Darling continued to live at 320 Commonwealth in 1933, but had moved to 387 Commonwealth by 1934.
By 1934, the Sanborns had resumed living at 320 Commonwealth and he had also moved his medical offices back there. Dr. Edward R. Williams also maintained his offices there; he and his wife, Helen Louise (Lutz) Williams, lived in Cambridge.
The Sanborns continued to live at 320 Commonwealth (and he continued to maintain his medical offices there) until about 1940, when they moved to an apartment at 384 Commonwealth.
In the spring of 1940, 320 Commonwealth was purchased by Mrs. Alice Jane (Eastman) Sawyer, the widow of Frederick W. Sawyer. The transaction was reported in the Boston Globe on May 5,1940. She previously had lived at 230 Newbury.
In June of 1940, Alice Sawyer applied for (and subsequently received) permission to convert 320 Commonwealth from a single-family dwelling into a lodging house. Alice Sawyer continued to live there until about 1957.
By 1961, 320 Commonwealth was owned by Barbara T. Curtin and Eastman Tuttle. They continued to operate it as a lodging house.
In August of 1961, real estate broker and investor Charles Talanian and his wife, Nevart (Semonian) Talanian, acquired 320 Commonwealth from Barbara T. Curtin and Eastman Tuttle. That same month, Charles Talanian applied for (and subsequently received) permission to convert the property from a lodging house into ten apartments.
In June of 1981, he converted the property into ten condominium units, the 320 Commonwealth Avenue Condominium.