Henry III's extension of the fortress east, beyond the old Roman city wall, involved the creation of a new curtain wall incorporating a series of towers, of which the Broad Arrow Tower was one.
The towers were actually designed for residential use as well as military, and as the inscriptions show this one also served as a prison cell. One room has now been furnished, complete with model of knight and dog to show how it would have looked when occupied by Sir Simon Burley, Richard II's tutor, who took refuge in the Tower during the Peasant's Revolt (1381). Seven years later, in 1388, he was to be victim of the first official execution on Tower Hill.
The origin of the tower's name is not clear; it could be from the broad arrows which were part of a medieval bowman's ammunition, or from the traditional broad arrow mark designating government property.