No plaque, no outline in the pavement, no surviving wall. The Lady Chapel, also known as St. Mary's Chapel, has vanished so completely that only archival records confirm it was ever there, and yet those records are unusually vivid, preserving the small, mundane details of a working religious building that served a Dublin parish for well over two centuries.

The chapel's earliest confirmed mention comes from 1346, when Christ Church Deeds refer to the new chapel of the Blessed Virgin Mary. It stood not inside St. Werburgh's Church itself, but as a separate structure projecting from the south side of its chancel, the eastern section of the church where the altar stood. A companion chapel, St. Martin's Chapel, occupied the equivalent position on the north side, and gave its name to St. Martin's Lane, a short passage between the church and Castle Street that survived until the eighteenth century before it too disappeared. J.L. Robinson, writing in the Journal of the Royal Society of Antiquaries of Ireland in 1914, drew on the churchwardens' accounts from 1484 to 1600 to describe both chapels in some detail. Each was lit by a single window. At their east ends, images of the Blessed Virgin and St. Martin stood not in wall niches but on brackets, or thrones, fixed to the stonework. The floors were tiled and strewn with rushes on special occasions. The accounts record a payment of twelve pence for tiling the Mary Chapel in 1495 to 1496, five pence in 1496 to 1497 for clearing rubble from its outer wall and carting it away in a wheelbarrow, and sixteen pence in 1567 to 1570 for a new iron bar for the chapel window. By 1577, the chapel had been formally annexed to St. Werburgh's Church.

St. Werburgh's Church of Ireland church still stands on Werburgh Street and is accessible to visitors; the medieval fabric it replaced is long gone, but the site itself is easy to find, a short walk from Dublin Castle. There is nothing to see of the Lady Chapel on the ground, and that absence is rather the point. The spot rewards the kind of visitor who finds value in standing somewhere and consulting what the documents say used to be there, imagining tiled floors, a single north-facing window with a new iron bar fitted sometime between 1567 and 1570, and an image of the Virgin on a bracket above the east wall.