481 Beacon was designed by architect Ernest N. Boyden and built in 1891 by John Hurley, builder, for real estate dealer Seth Russell Baker, one of two contiguous four-unit apartment houses (479-481 Beacon).
A third four-unit apartment house was built at 483 Beacon at about the same time, and probably was a companion to 479-481 Beacon. It was razed in about 1898 for construction of the Hotel Cambridge. Also in 1891, Ernest Boyden designed and John Hurley built two additional multi-family buildings for Seth Baker across Massachusetts Avenue at 491 Beacon (21-23 Massachusetts) and 25-27 Massachusetts.
Washington Thomas and his wife, Caroline (Wadleigh) Thomas, lived at 20 Gloucester. He was a sugar manufacturer and an investor in real estate. In 1895, he had built The Marlborough apartments at 416 Marlborough.
Washington Thomas continued to be shown as the owner of 479-481-483 Beacon and 416 Marlborough on the 1898 and 1908 Bromley maps, and was the assessed owner of all four properties through 1911.
By 1912, 479-481-483 Beacon and 416 Marlborough were owned by Leslie C. Wead et al, trustees. They continued to be the assessed owners of 479-481-483 Beacon through 1917 and of 416 Marlborough through 1918, and are shown as the owners of all four properties on the 1917 Bromley map. Leslie Wead was a lawyer and real estate trustee, and was acting as trustee of the Thomas family’s investments.
By 1919, 479-481-483 Beacon and 416 Marlborough were owned by the Marlborough Real Estate Trust, which was the assessed owner from 1919 through 1921. By 1922, Herbert G. Sumner et al, trustees of the Thomas Trust, were the assessed owners of all four properties.
By the mid-1920s, 479-481-483 Beacon had been converted to be primarily medical offices, with some residential apartments.
Washington Thomas died in May of 1929 and Caroline (Wadleigh) Thomas died in May of 1939.
479-481-483 Beacon and 416 Marlborough continued to be owned by the Thomas estate. Herbert G. Sumner et al, trustees, were the assessed owners through 1949, and William Tudor Gardiner et al, trustees, were the assessed owners from 1950 through 1954. William T. Gardiner was Washington and Caroline Thomas’s son-in-law, the husband of Margaret (Thomas) Tudor. He was a lawyer and had served as Governor of Maine; he died in August of 1953.
By 1955, 479-481-483 Beacon and 416 Marlborough were owned by Miss Katherine F. Ladd, who was the assessed owner of all four properties from that year. She was a secretary with Dreyfus Properties, which managed the buildings, and appears to have held them in her name on their behalf. She lived in Roslindale.
In March of 1971, 479-481-483 Beacon were acquired from Katherine Ladd by Harold Brown and Robert J. Samia, trustees of the Beacon Towers Trust. The same month, 416 Marlborough was acquired by the Back Bay Trust (David H. Greenberg, Albert L. Manley, Joel B. Wilder, and Leonard S. Green, trustees).
In February of 1982, Harold Brown and Robert Samia converted the property into the Beacon Tower Condominiums with 85 Units: 8 units in 479 Beacon, 8 units in 481 Beacon, and 69 units in 483 Beacon.