The parish church of St Gwyddan was built around 1500, with the south chapel added between the 1570's and 1580's. It has walls of local slatey rock and a roof of rough graded slates. There is a contemporary bellcote with an arched bell opening. The interior contains exceptional historic details including a perpendicular style rood screen, probably taken from a fifteenth century predecessor church, a central Tudor arch, carved 'bent feather' spandrels and 2 windows retaining original sixteenth century glass. The lych-gate associated with the church was accidentally demolished in 2006.

Source: CADW listed buildings database
RCAHMW, 7 November 2007.

[Additional:] RCAHMW tree-ring dating with site description reported in Vernacular Architecture 42 (2011):

CAERNARFONSHIRE
DOLWYDDELAN, Parish Church of St Gwyddelan (SH 7359 5229) Nave Roof Felling date range: 1471-1501
Collar 1467(2); Arch braces (1/2) 1453(H/S); Principal rafter 1466(1); Purlins 1458(H/S), 1458(H/S). Site Master 1360-1467 STGWYD (t = 7.2 PENGWERN; 7.2 WALES97; 7.0 WICK).
St Gwyddelan's Church has a roof of archbraced collar-beam trusses with cusped windbraces. The trusses are boarded and painted over the chancel. The church is of particular interest because documentary references suggest that the parish church was rebuilt on a new site c. 1500. According to Sir John Wynn of Gwydir, the present church was built by his ancestor Maredudd ap Ieuan who acquired Dolwyddelan Castle in 1488 and rebuilt the church because he feared being ambushed at the more remote old church. The felling-date range of 1471-1501 obtained for the nave roof is consistent with this tradition. Plan and account in RCAHMW, Caernarvonshire Inventory, Volume I: East (1956), pp. 76-80. Dating commissioned by RCAHMW. (R.F. SUGGETT/RCAHMW/July 2011).