The name of the fashionable London suburb was chosen by James Entwhistle, a speculative builder, who developed much of Sydenham as a residential area, presumably as being more high sounding than Strandtown.
The earliest reference we have been able trace is a newspaper advertisement in the Belfast Mercury, 20 August 1856: "to be let, with immediate possession, if required, the beautifully-situated Villa Residence, SYDENHAM, at present occupied by Major-General Govan, C.B., one mile and a half from Belfast, on the Holywood Road." It seems, therefore, that the name was first given to this house before being extended to other buildings, such as the railway station, and then to the locality in general, or at least to the area in which fashionable, new houses were built. To some extent, this may have been apt because Sydenham in Kent had many fine houses of remarkable architectural style. However, much of this Victorian development only took place in the 1860s and later. An important factor which helped the name to catch on in Belfast was surely the relocation of the Crystal Palace to Sydenham, Kent, in 1854, just two years before the newspaper advertisement cited above. The Great Exhibition had taken place inside this glass building in 1851 when it was sited in Hyde Park, but the Crystal Palace was also visited in Sydenham by huge crowds, no doubt including some of the wealthy elite of the Belfast area.
Resolved--That the names " Sydenham Park" and " Sydenham Crescent " be approved for new streets off Holywood Road on the property of Mr. Joseph McMaster. (8th February 1938).