A mural tower, meaning a tower built into and forming part of a defensive wall rather than standing independently, it is one of the quieter remnants of the circuit that once enclosed the medieval city. Most Dubliners pass close to it without registering what it is.

The tower's earliest documented history goes back to 1259, when the Dublin White Book recorded a grant giving Master Hugh de Kyngesbury the use of the tower in Rochelle Street, as the lane was then known, for life, with the city reserving the right of free entry and exit in time of war. By 1585, the tower was in the possession of a Christopher Sedgrave, whose name it still carries informally. A detailed survey from that year, recorded in the Calendar of Ancient Records of Dublin, gives an unusually precise physical description: a demi-round tower with two vaulted chambers, three arrow loops, a garret, and a set of stairs rising from the wall walk to its upper level. Its dimensions were recorded as 26 feet high, 4 feet thick in the walls, roughly 11 feet by 6 feet in internal floor area, with enough covered space at the top for a few people to stand. The same survey notes it sat 103 metres from the tower then held by Sir William Sarsfield, and 27 metres from the tower of one Richard Fagan. That kind of granular, street-by-street accounting reflects a city taking stock of its own defences at a particular moment of civic concern.

The tower stands in Lamb Alley, accessible on foot from Back Lane or Rochelle Street in the Liberties area of Dublin's south city. The surrounding streetscape is dense and workaday, which is part of what makes finding the wall remnants here feel like an accidental discovery rather than a managed heritage experience. The original staircase that connected the tower to the wall walk no longer survives, so the structure cannot be entered, but the exterior stonework is visible from the alley. The area rewards a slow walk: several sections of the medieval wall survive in this stretch, and the fabric of the stonework, where it has not been absorbed into later buildings, gives a reasonable sense of the wall's original scale.