The bell tower to the north is a 60 feet (18 m) high two-storey octagonal stone building with pointed louvred windows.

The Buildings of Wales describes the slope as setting "the cathedral and Bishop's Palace in a green bowl" with 39 steps leading down the steep incline from the gateway.

[3] What is nowadays the bell tower was used by the bishops of St Davids for their consistory court and a record office for the episcopal see.

[2] Joseph Lord's 1720 map of the Cathedral Close clearly shows a plan of Porth-y-Tŵr, describing it as "The East gate and rooms adjoyning to it where the Bishop's & Mayor's courts were held".

[8] Porth-y-Tŵr was in ruins by the 20th century and, in 1929, the octagonal tower was substantially restored by ecclesiastical architect W. D. Caroe,[1] with funding coming from an anonymous donor.