This room is of great architectural importance and is considered to be the cornerstone of the Cathedral. It is located in the heart of the Belfry Tower and was shored up and strengthened in the 18th century after the fire of 1705 and the earthquake of 1755 so as to support the cathedral.
It is a large vaulted room that witnessed the tragic events of the 18th century. Stones blackened by fire, cracks caused by the earthquake, marks on the masonry, hollows in the beams, interior iron hoops, etc. make it even more spectacular.
It contains the oldest document of privilege of Salamanca (1102) and El Cid’s pectoral cross, together with a 12th century Arabian canvas and documents from the time of the construction of the Old Cathedral (12th to 15th centuries).
The design plan of Santa María de la Sede, or the Old Cathedral, included two towers at its foot, a lower one used to defend the enclosure and known as the Flat-topped Tower, and another higher one that is the Belfry Tower. In the heart of the Belfry Tower lies the Vault Room, which is of considerable size and is covered with a pointed barrel vault, with a transverse arch in the centre and ribs standing against the walls, which originate at medium height on corbels.
The walls and the vault are built of the sandstone blocks of Villamayor, and show signs of carving and stonemason’s marks.
Together with these traces, two huge trunks shore up the room together with several iron bands or cramps so as to strengthen the structure of the room and of the remainder of the Belfry Tower.
In 1705 the Belfry Tower caught fire on being struck by lightning. Considerable damage was done to the walls to leave the marks that can be seen today; the upper section was destroyed and some of the bells were melted. The master Pantaleón Pontón Setién repaired the tower and continued to increase its height with the addition of an upper section as from the level of the cornice. Shortly afterwards the excess weight of the baroque crowning ruined the Romanesque shaft; this was subsequently aggravated by the effects of the Lisbon earthquake on 1st November 1755.
The masters of the period were consulted as to restoration and finally the proposal of Baltasar Devreton was accepted; it was executed by the young Jerónimo García de Quiñones.
The room was inhabited for centuries by bell founders and other servants of the Cathedral and their families.