As a square, not of great distinction; as an open space providing a focus and centre for the town, important. In 1801, Coote says: 'a handsome square, which has the court house in the principal front, with a new town clock, commands one entrance, and here the linen market is held on Mondays'. The old courthouse disappeared early in the century; the hiring cross was removed in the 1870s to make way for the Rossmore memorial in the centre of the square, to its present site in Old Cross Square. If an adequate car-park could be built near-by, and the feeling of spaciousness restored by banning parking and planting mature trees, the Diamond would be greatly improved.
In 1835, John O'Donovan noted: 'The large house in the Diamond opposite Glasslough Street is said to occupy the site of a Castle ... in the rear of this, some old walls are to be seen, said to be the remains of an old Abbey".
Rossmore Memorial, The Diamond:
c. 1875; architect unknown. A formidable High Victorian fountain of red sandstone, now deeply weathered, in the very centre of the square on an octagonal plinth of two granite steps. The eight letters R-O-S-S-M-O-R-E are strung conveniently around the octagon above. There is an inscription, "In memory of the Rt. Honble Henry Robert 4th Baron Rossmore who died at Windsor 28th day of March 1874 in his 23rd year"; another inscription, now wholly illegible; and a scattering of escutcheons and badges. The central pink marble column supports a drinking bowl: around this, eight grey marble columns with floral sandstone capitals, support the pinnacled superstructure on pointed arches; the finial is borne on eight more little columns, this time of granite; the weathercock, the original railings, and the drinking trough, have now disappeared. It would be nice if the fountain could be restored.
The appearance of this striking, if at present rather unfashionable, monument is greatly disimproved by the fact that immediately beside it stands an enormous silver painted steel pole carrying no less than 41 wires, and a lamp; and by three traffic direction signs.