Biography: Frank Ellis Alden was born in Edgartown, Massachusetts and studied architecture at the Massachusetts Institute of Technology. In 1880 he began working in the office of H. H. Richardson. After Richardson's death he joined the partnership of Alexander Wadsworth Longfellow, Jr. and Alfred Branch Harlow in 1886. This partnership with Longfellow continued for a decade until it dissolved in 1896. Alden continued to work with Harlow in the firm Alden & Harlow until his death in 1908.

Biography: Longfellow, Alden & Harlow was a Boston and Pittsburgh-based architecture firm founded in 1886 by Alexander Wadsworth Longfellow, Jr. and Alfred Branch Harlow. In 1887 Frank Ellis Alden joined the firm as a partner. Both Longfellow and Alden had previously worked in the Boston office of H. H. Richardson and Harlow worked for McKim, Mead & White. The firm was active in both Boston and Pittsburgh until 1896 when the partnership dissolved; A.W. Longfellow, Jr. continued his practice in Boston and Alden & Harlow formed their own firm in Pittsburgh.

Biography: Alexander Wadsworth Longfellow, Jr. was the son of Alexander Wadsworth Longfellow, Sr. (1814-1901), a U.S. Coast Survey topographer, and of Elisabeth Porter. After graduating from Harvard University in 1876, he studied architecture at the Massachusetts Institute of Technology and the École des Beaux-Arts in Paris, then worked as senior draftsman in Henry Hobson Richardson's office. After the death of H. H. Richardson he formed a partnership with Frank Alden and Alfred Harlow, His work was primarily in Boston with the firm Longfellow, Alden & Harlow which designed the Massachusetts City Hall, Cambridge, Massachusetts and the Carnegie Library in Pittsburgh, Pennsylvania. He resigned from the firm in 1896 and continued his own practice based in Boston. Longfellow was a trustee of the Boston Museum of Fine Arts and the Boston Athenaeum.