Full Report for Listed Buildings

Summary Description of a Listed Buildings

Reference Number
Building Number
Date of Designation
Date of Amendment
Name of Property
Priory Church of St Seiriol  


Unitary Authority
Isle of Anglesey  
Street Side
Slightly set back from the N side of a country road which leads down to the SE tip of the island at Black Point, or Trwyn Du, Penmon.  


Broad Class
Religious, Ritual and Funerary  

The Church is said to have been founded in the first half of the C6 by Cynlais, who placed it in the charge of his brother Seiriol. The oldest part of the present building is the nave, built during the early years of the reign of Owain Gwynedd, c.1140, and in 1160-70 the central tower and transepts were added. In 1237 Llewelyn ap Gruffydd (Fawr) granted the monastery to the Prior and cannons of Priestholm (Puffin Island). The Prior transferred his seat, built a large new chancel to replace the original and a cloister to the S around which domestic buildings were arranged. By 1414 it had become the Priory Church of St Augustine. The chancel was rebuilt in the C15 and again during the 1853-5 restoration by Weightman and Hadfield; the N transept and E wall of the S transept were also rebuilt at this time. The interior of the church contains some re-set C12 stones, and the E window in the S transept re-uses some C15 glass from the earlier chancel window. The chancel contains a C13 weathered bronze which was found near the altar when the chancel was rebuilt in the mid C19.  

Priory Church built to a cruciform plan, with central tower over crossing. Stone built with mid C19 and later slate roof with cross gable finial at chancel; pyramidal stone roof to tower. The oldest part of the church is the C12 nave of 2 bays. The N wall has a restored chamfered plinth and an original pilaster-buttress with modern coping, E of which is an original window with round head. The C13 N doorway has chamfered jambs and a shouldered arch. The S wall has plinth and buttress similar to that of the N wall and opposing openings with similar window. The original S doorway has jambs of 2 orders, the inner square, the outer with detached shafts with scalloped capitals and roll-moulded bases. The arch is of a single roll-moulded order enclosing a tympanum on which is carved a beast with head turned backward biting its forked tail; a band of 4-cord interlaced work forms the border. The W wall has a chamfered plinth and an original round-headed window with round rear-arch. The mid C12 central tower is square in plan, 2 stages and surmounted by a squat pyramidal stone spire with roof of small old slates; the 2nd stage string is a mid C19 addition. Only the upper stage is visible from the outside of the church; it has a window in each wall of 2 round-headed lights, the central columns with cushion capitals and square bases (those in S and W walls are replacements). The S transept is contemporary with the central tower, the E wall rebuilt during the mid C19 restoration. The S wall has an original window with later blocking. The N transept was rebuilt on the original foundations in the mid C19, paired round-headed lights in the N gable and round-arched light in the E wall as for the S transept. The chancel was rebuilt in 1855; 2 bays each with paired trefoiled lights and pointed arched doorway in the SE angle under a timber porch on stone walling. The doorway has hollow chamfered jambs of 2 orders. The E window has cusped tracery over 3-trefoil lights in a pointed arched frame with hoodmould.  

The C12 nave has deeply recessed windows with widely splayed reveals set high in the walls. The font stands at the W end of the nave: c1000, originally the base of a cross returned from Beaumaris in the C19, square in plan and tapering to the top, 3 of the sides decorated with Celtic fret, diaper, key pattern and triquetra knots; the 4th side plain. C12 pillar piscina; a rectangular stem with a scalloped and foliated cap and roll-moulded base. Above the tower arch in the E wall of the nave are 3 carved stones; 2 with human faces, the 3rd with 2 faces, probably C12. The lower stage of the tower has a round crossing arch in each wall, all original except for that in the N wall, rebuilt during the mid C19 restoration. The E arch has square jambs and plain impost; masonry plastered. The S arch has jambs of a single order, square on the S and with attached shafts on the N; with scalloped capitals and roll-moulded bases, the E shaft is semi-hexagonal and decorated with chevrons, the arch plain on the S side and decorated with bands of chequer, chevron and bead-and-reel on the N. The W arch has plain jambs to the E and of 2 orders to the W, each with attached shafts, the outer round, the inner chamfered or grooved,with roll-moulded bases; 3 capitals are crudely carved, the fourth scalloped. The chamfered imposts are enriched with semi-circles, triangles and zig-zags. The outer order of the arch is decorated with chequer and chevrons, the inner roll-moulded. The 2nd stage of the tower has a small window in the S wall, opening into the transept; with round rear arch and splayed reveals. Along the S and W walls of the S transept is an arcade of round arches, 5 to each wall, carried on attached shafts with scalloped capitals, chamfered imposts and roll-moulded bases on chamfered plinths; the arches vary in width and are decorated with chevrons. Most of the shafts are round, some with central bands; 2 on the W wall are square with chevron enrichment, and 1 in the SW corner is twisted. Above the arcade is a moulded string. Built into the mid C19 E wall of the S transept is a wheel cross, formerly sited at the apex of the tower. The mid C19 E window represents St Christopher and St Seiriol and has re-set within it 7 fragments of the C15 E chancel window. Also re-set into the walls of the S transept are 2 carved stones, one a C12 'Sheila-na-gig', a weathered figure of a woman with legs apart; the other a Medieval depiction of a bearded man's head and shoulders with axe held in his right hand. Standing in the S transept is a cross, c1000, which was formerly used as a window lintel in the refectory. The shaft and head of the cross are a single stone; now with a modern base. The N and S faces of the cross are decorated with Celtic knotwork and key-pattern designs; edge panels terminating in beasts' heads. Set into the N wall of the chancel is a C12 plain latin cross and displayed in a glass case is a C13 bronze plaque of Limoges enamel depicting a demi-figure of Our Lord with a red nimbus, his right arm raised in benediction. Re-set into the S wall of the chancel are several C12 stones decorated with chevrons. There are a number of C17 and C18 memorials including one bearing the arms of Wilsford, a chevron engrailed between 3 leopards' heads and flanked by a winged hour glass and a skull, to Sir Thomas Wilsford of Ildinge, Kent d1645.  

Reason for designation
Listed as the church of an important early monastic foundation with substantial high quality work of the C12, housing a series of important Christian stones; the centre piece of a monastic estate which includes the surrounding conventual buildings, the nearby holy well and cell and also the monastic remains at Ynys Seiriol. Ancient Monument No 1/1838/AN 027 (ANG) G.  

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