Adelphi // (from the Greek adelphoi, meaning "brothers") is a district of the City of Westminster in London. The small district includes the streets of Adelphi Terrace, Robert Street and John Adam Street.
The district is named after the Adelphi Buildings, a block of 24 unified neoclassical terrace houses occupying the land between The Strand and the River Thames in the parish of St Martin in the Fields, which also included a headquarters building for the "Society for the encouragement of Arts, Manufactures and Commerce" (now generally known as the Royal Society of Arts). They were built between 1768–72, by the Adam brothers (John, Robert, James and William Adam). The ruins of Durham House on the site were demolished for their construction. The nearby Adelphi Theatre is named after the Adelphi Buildings. Robert Adam was influenced by his extensive visit to Diocletian's Palace in Dalmatia, and applied some of this influence to the design of the neoclassical Adelphi Buildings. Many of the Adelphi Buildings were demolished in the early 1930s and replaced with the New Adelphi, a monumental Art Deco building designed by the firm of Collcutt & Hamp; buildings remaining from the old Adelphi include 11 Adelphi Terrace (formerly occupied by numismatic specialists A.H. Baldwin & Sons Ltd) and the Royal Society of Arts (which has expanded to incorporate two of the former houses).
- Edward Litt Laman Blanchard, writer, lived in Adelphi Terrace from 1876 to 1889
- David Garrick lived for his final seven years, and died in 1779, in the centre house of the buildings.
- Thomas Monro, Physician to George III and art patron, owned a house in Adelphi Terrace.
- Richard D'Oyly Carte, Victorian impresario
- Sir J M Barrie (1860–1937), playwright and novelist, author of Peter Pan, at Adelphi Terrace
- John Galsworthy, novelist, author of The Forsyte Saga
- George Bernard Shaw, Irish playwright, Fabian socialist, co-founder of the London School of Economics and Political Science
- Thomas Hardy, English novelist
- Charles Booth, Shipyard owner, Philanthropist, coordinator and co-author of the monumental Life and Labour of the People in London (1880–1900).
- Fictional detective Gideon Fell, created by John Dickson Carr, lived at no. 1, Adelphi Terrace.
- David Copperfield, created by Charles Dickens, lived in Adelphi.
- Mills, A., Oxford Dictionary of London Place Names, (2001)
- Peter De Bolla, The Education of the Eye: Painting, Landscape, and Architecture, 2003, Stanford University Press. 296 pages ISBN 0-8047-4800-4
- C. Michael Hogan, "Diocletian's Palace", The Megalithic Portal, Andy Burnham ed, Oct. 6, 2007
- 'The Strand, southern tributaries – continued', Old and New London: Volume 3 (1878), pp. 100–110 accessed: 30 May 2008
- Brereton, Austin. The literary history of the Adelphi and its neighbourhood (New York: Duffield, 1909). Illustrated.