The twin chimneys of No. 23.

Number twenty-three is the oldest of the three houses. The Dublin Civic Trust dates it to between 1670 and 1725, and its floor plan holds a small architectural surprise: two chimney stacks set close together in the middle of the building, dividing the front and back rooms.

It is a layout drawn from Joseph Moxon's Mechanick Exercises, published in London in 1677 - a builder's manual that shaped much of Restoration-era terraced housing in the English capital. Very few Dublin houses of this plan survive. Most were rebuilt in the eighteenth or nineteenth century as tastes and fortunes changed.

Number twenty-three kept its chimneys. It has otherwise been through the mill: the front façade was refaced in yellow Dolphin's Barn brick around 1900, the rear was rebuilt at roughly the same time, two shopfronts were cut into the ground floor, and from 1896 to 1921 it was let out as tenements. Nevertheless the bones of a Restoration-London townhouse are still there, one storey above the pavement.

You can see the twin stacks clearly from the walled yard at the back, at dusk, when the roofline stands against the sky.