The ancient parish of Llandysilio, or in full Llandysilio yn Iâl, was divided into three parts (the Welsh word 'traean' means 'one-third' in English) named Llandysilio Traean, Trefor Traean, and Glyn Traean. The place name can often be seen with the spelling 'Llantysilio'.
Llandysilio Traean contained the townships of Bachau, Cysylltau,
Llandysilio Abad, Llandysilio Fawr, Llandysilio Fechan,
Feifod, Pengwern and Rhisgog.
Trefor Traean contained the townships of Cilmediw, Dinbren, Eglwysegl, Trefor Isaf and Trefor Uchaf.
Glyn Traean contained the townships of Cilcochwyn, Crogen Iddon, Crogen Wladys, Erwallo, Hafodgynfor, Nantygwryd, Pennant and Talygarth.
On 15 April 1848, the whole of Glyn Traean, together with the township of Cysylltau from Llandysilio Traean, went to form the new parish of Pontfadog. Hovever, Cysylltau returned to Llandysilio in 1870.
There has been a church in Llandysilio since probably the sixth or seventh centuries. A new building was erected in the thirteenth century; and another, probably in the early sixteenth century, following a fire. The tower was built circa 1750. The church was restored and extended between 1876 and 1883.
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For family history information about the church and parish, visit the GENUKI Llandysilio page.