The founder of the original church of St. Asaph was Saint Kentigern, also known as Saint Mungo. He was a late 6th century missionary in the Kingdom of Strathclyde in what is now Scotland and a patron saint and founder of the city of Glasgow. The “Life of Saint Mungo” was written by the monastic hagiographer, Jocelin of Furness in about 1185. Jocelin states for some thirteen years, Kentigern labored in Strathclyde, living an austere life in a small cell and making many converts to Christianity by his holy example and his preaching.
When a Strathclyde king started a strong anti-Christian movement, Kentigern was forced to leave the district. He traveled to Wales, staying with Saint David and afterwards moving on to Gwynedd where he founded a church at Llanelwy. Soon, a new king in Strathclyde invited Kentigern to return to his kingdom. He decided to return and when Kentigern died in 596, a local Welsh saint, Asaph, took his place in Llanelwy. St. Asaph’s name and reputation were to take on greater significance when a new territorial episcopal see was created at Llanelwy.
Around 1073, the first bishop, Gilbert, was consecrated at St. Asaph’s. The second bishop, Geoffrey of Monmouth, was consecrated in 1152. Monmouth is best known for his chronicle “History of the Kings of Britain” and for popularizing the tales of King Arthur. It is unknown if Monmouth ever visited his bishopric. The earliest parts of the present building date from the 13th century when a new building was begun. Scholars believe the new cathedral was built on a site some distance away from the original parish church. By 1281, the relics of St. Asaph had been removed from the old building and enshrined in the newly-built cathedral. Some of this work can be seen today in the gables and chamfered buttresses on the west front, the southwest corner buttresses and the walls of the early English choir.
It is believed the church was vandalized by soldiers of King Henry III of England in 1245. The bishopric was out of favor with Llwelyn ap Gruffydd, the last Prince of Wales during that time. St. Asaph’s Bishop, Anian, sought the protection of King Edward I who wanted the church moved to Rhuddlan and promised land and one thousand marks. The project was abandoned when on Palm Sunday in 1282, the Welsh revolted and sacked the castle at Hawarden. Later that summer, English soldiers accidentally burned down the cathedral. Anian fell from favor and the new bishop insisted on rebuilding.
The great restoration of the cathedral lasted from 1284 to 1381 with money from pilgrims who came to worship at the shrine of St. Asaph. The bell tower was added in 1391. After all this careful restoration, the cathedral was to be burned down again by Owain Glyndwr’s Welsh troops in 1402. The building was reduced to ruin until repairs were begun in 1471. Most of the rebuilding was completed during the reign of King Henry VII.
During the reign of Queen Elizabeth I, St. Asaph was the focus of an enterprise crucial to the survival of the Welsh language – a translation into Welsh of the Bible and Prayer Book. The translators were led by Bishop William Morgan and other clergy of St. Asaph and there is a memorial to them on the Cathedral Green. In 1715, the tower was completely demolished by a fierce storm. The building we see today is largely 14th century with many Victorian alterations and remodeling which took place from 1867-1875. St. Asaph claims to be the smallest Anglican cathedral in Great Britain.