The conservation works at the Moorish Castle are accompanied by a research programme that aims at obtaining as much information as possible about the monument and its evolution. Most discoveries add small nuggets of information that add to the picture. Sometimes the exploration takes us into a new level of understanding. This has happened very recently.

Conservation works on the north-western side of the Tower of Homage required the erection of a scaffold. These works were delayed because common kestrels and jackdaws were found to be nesting in holes in this part of the tower. The delay paid dividends as both species bred successfully, the first time in many decades in the case of the jackdaws. With the end of the breeding season the scaffold was erected and conservation works commenced.

It soon became clear that a hole that had been sealed on the mid-level battlements, which had been covered by a fig tree, and through which an electrical cable had been hung, was no ordinary opening in the battlements’ floor. Seeing this, the floor tiles which had been placed on the surface of the battlements during restoration works in the 1970s were removed from immediately above the hole. The opening was discovered to have been crafted deliberately in the construction style of the North African Merinids, who had enlarged the Tower in 1344. The repair and enlargement of the tower, to the size that we know it at present, happened at this time as Gibraltar’s defences were strengthened after the defeat of the combined Muslim forces of the North African Merinids and Granada Nasrids at the hands of the Castilians and Portuguese, west of the Rock.

The purpose of the hole was that of a Murder Hole (a Meurtrière), typically a hole in the ceiling of a passageway in a fortification through which the defenders could shoot, throw or pour harmful substances or objects; these could have included rocks, arrows, boiling water or oil, hot sand, or quicklime. The location of the Murder Hole was highly significant, being situated directly above the only access door to the tower, which had been located there during the enlargement of the tower. This gave the hole added significance as it could have doubled-up in function to act as a Quenching Hole, through which water could be poured should the attackers set fire to the main door leading to the Tower.

This defensive mechanism would only have worked if substances could be poured vertically down onto the space immediately outside the door itself. Without the hole, the space would have been a blind spot for the defenders. The peculiar shape of the Tower of Homage at its north-western end, with a passageway between the western and northern mid-level battlements, is now easily understood as the passageway was needed in order to locate the Murder Hole just above the tower’s entrance. This would have been the last line of defence. The finding also explains why the expansion of the tower northwards, to incorporate the covered stairwell, did not follow the line of the earlier tower to form a square. Instead, the recess allowed for the passageway, the Murder Hole and the location of the door directly below it.

The Minister for Heritage, the Hon Prof John Cortes, said: "The value of the work being done at the Moorish Castle under the expert supervision of the Gibraltar National Museum goes beyond providing a better visitor site and is revealing new information giving insights into our fascinating but less well-known medieval history. The value of the Government’s commitment to unlocking this work and proceeding with the restoration of the Moorish Castle is clearly benefitting the knowledge of our Heritage.”

Tower of Homage showing location of Murder Hole in relation to 1344 works

Detail of the Murder Hole

Professor Clive Finlayson exploring the newly-discovered Murder Hole