Newport Cathedral (), also known as St Gwynllyw's or St Woolos' Cathedral, is the cathedral of the Diocese of Monmouth within the Church in Wales, and the seat of the Bishop of Monmouth. Its official title is Newport Cathedral Church of St Woolos, King and Confessor. The English name, Woolos, is an anglicisation of the Welsh name Gwynllyw.

It became a cathedral in 1949 and while it is the size of a large parish church rather than a typical cathedral, its history and development from the sixth to the twentieth century make it arguably one of the most interesting religious buildings in Wales.

St Gwynllyw

thumb|St Gwynllyw with St Gwladys and St Cattwg fancifully depicted in a 19th-century window in the south aisle

The church was founded by St Gwynllyw, who lived in the later fifth century, after the Roman occupation, at a time when Wales was beginning to develop a national identity. Gwynllyw was the king of Gwynllwg, an area which lay between later Glamorgan and Gwent. There seems little doubt of his historical existence as a real person, although miraculous events are associated with his life and burial place. He was alleged to have been originally a merciless warrior against adjoining kingdoms, a robber and a pirate. Later in life, he converted to Christianity, having been told in a dream to follow a white ox to the prominent hill where he built a church, probably of wood. The shape and footprint of this original church is reflected over 1500 years later in St Mary's chapel at the west end of the cathedral. The church became his burial place (Welsh: eglwys y bedd), and in succeeding centuries was a significant place of pilgrimage. It was subject to plundering and attack including, it is said, by Irish pirates and Danes, and in 1060 by followers of Harold Godwinson, the last Anglo-Saxon king.

Gwynllyw is venerated in Wales and in the Roman Catholic and Eastern Orthodox traditions. He was the husband of St Gwladys and their son was one of the greatest of all Welsh saints and scholars, Cadoc (Cattwg in Welsh).

A much greater transformation took place at the site in the later twelfth century when a large new church was built in the Romanesque style with round-headed arches, favoured by the Normans. Instead of building this new church directly on the original site of Gwynllyw's church, it was built to the east, but attached to it, respecting the sanctity of the original site and indicating of the strength of the cult of Gwynllyw.

In the 14th century, the castle was replaced by a new castle on the bank of the River Usk. The town of Newport (Casnewydd in Welsh, meaning 'new castle') grew near the castle and river.

alt=The view from the roof of the tower of St Woolos Cathedral|thumb|The view from the roof of the tower of St Woolos Cathedral

The tower contains a ring of 13 bells, the largest ring of bells in Wales. Although a fine tower, it is separated from the main body of the church by St Mary's chapel. It is not certain whether there was an earlier tower on the site.

St. Mary's Chapel

thumb|St Mary's Chapel looking towards the east with the font in the foreground

To enter St Mary's chapel, which now links the tower with the main body of the cathedral, we pass through a modern glass screen engraved with representations of St Gwynllyw holding his church and of St David (Welsh: Dewi Sant), the patron saint of Wales, with a dove on his shoulder.

St Mary's was the original site of Gwynllyw’s church, (though much restored and rebuilt in the 11th, 13th and 19th centuries) and the site of his tomb, (Welsh: bedd y sant), which is believed to have been on the south side of the building. This chapel is a place to savour the established tradition of Celtic Christianity in Wales, which long predates the arrival of St Augustine to convert England.

Towards the west end of the chapel is a splendid Victorian reconstruction of a Romanesque font based on a surviving fragment of the original which has been incorporated in the later work. The shaft and base of the font look medieval.

The Romanesque portal

thumb|The great Romanesque portal leading from St Mary's Chapel to the main body of the cathedral to the east

It is from St Mary's chapel that we first view the chief glory of the cathedral – the wonderful twelfth-century Romanesque portal with its characteristic zig-zag chevron motifs framing the iconic view of the main body of the cathedral. The outer order of decoration is derived from Gloucester Cathedral, while the inner order has parallels in the Herefordshire School of Romanesque Sculpture. There are some remains of paint on parts of the portal, and it was almost certainly fully painted originally. The site of the archway may well mark the site of an opening to an earlier, smaller chancel, perhaps ending in an apse, before the major extension of the church took place. One theory is that they had been brought here at a rather earlier date to form part of the shrine which may have previously existed over Gwynllyw’s grave and subsequently relocated into the portal to lead the way into the new building. If so, they would be symbols of the power of his cult and the desire of the Anglo-Norman conquerors of Wales to associate themselves with him.

The capitals are of Roman Composite type and, if they were indeed also originally Roman, they have been recut. Over generations, scholars have debated what the scenes represent. They were thought to be Biblical scenes – the Creation, Fall, Flood, Baptism of Christ, and the Trinity. Scenes from the lives of Gwynllyw and Cattwg have also been suggested. More recently, it has been suggested that they were intended to be understood on two levels as the scenes may have echoes both in the Bible and in the lives of the two saints honoured at this site. The style of the hair and tunics on the figures on the north (left-hand) capital echoes fourth-century Roman art which suggests that we are indeed contemplating sculpture which looks back to the very earliest phase of Christianity in Britain.