[citation needed] Between the years 835 and 998 the cathedral was devastated approximately 16 times, so that when the Norman, Ralph of Bristol, became bishop in 1223 it was virtually in ruins.

Between then and 1230 it was largely rebuilt, likely in the years following 1223, and probably by Ralph of Bristol who was made Bishop of the see in 1222 and died in 1232.

These works included a new north transept, new chancel, and new west wall as well as rebuilding three sides of the square tower.

[5][6] Beside the cathedral stands one of County Kildare's five round towers which is 32 metres (105 ft) high, and which can be climbed at certain times.

The cathedral is cruciform in plan without aisles in the early gothic style with a massive square central tower.

The parapets are of the stepped Irish type (now much restored) but probably datable to c. 1395, the year in which a Papal relaxation was given to those who visited Kildare and gave alms for the conservation of the church.