This venerable cathedral is set in a hollow near the River Taff, on the site of a 6th-century monastery founded by St Teilo. The present building was begun in 1120, but it crumbled throughout the Middle Ages, and during the Reformation and Civil War it was used as an alehouse and then an animal shelter. Derelict by the 18th century, it was largely rebuilt in the 19th century, and then repaired again following a German bombing raid in 1941.

　　The towers at the western end epitomise the cathedral's fragmented history – one was built in the 15th century, the other in the 19th. Inside, a giant arch supports Sir Jacob Epstein's huge aluminium sculpture Majestas, its modern style a bold contrast in this gracious, vaulted space. Pre-Raphaelite fans will appreciate the Burne-Jones reredos (screen) in St Dyfrig's chapel and the stained glass by Rossetti and William Morris' company.

　　Medieval effigies recline beneath tattered and tasselled Union flags, St Teilo's tomb is located on the south side of the sanctuary, and other signs of early Christianity – a Celtic cross near the chapter-house door and gravestones reused as construction materials – are visible.