"LANDELOY (LLAN-DYLWYV ) a parish in the hundred of DEWISLAND, county of PEMBROKE, SOUTH WALES, 7 miles (E. by N.) from St. David's, containing 217 inhabitants. This parish, which derives its name from the dedication of its church, is pleasantly situated in the north-western part of the county. The living is a discharged vicarage, annexed to that of Llanhowel, in the archdeaconry and diocese of St.David's, rated in the books at £5, endowed with £800 royal Bounty and £200 parliamentary grant. The church, dedicated to St. Teilaw, is not remarkable for any Interesting architectural features. The average annual expenditure for the support of the poor is £65.18." [From A Topographical Dictionary of Wales (S. Lewis, 1833).]
The parish name question
" The present dedication of this LLAN to St. Teilo is a mistake dating from the time of Browne Willis. It has been suggested that the founder's name may have been TYLWYF, a compound of the honorific TY and Llwyf 'elm trees', but no such name is on record." ( B. G. Charles in The Place-names of Pembrokeshire )
Melville Richards in Enwau Tir a Gwlad also opts for Ty + Llwyf giving Llandylwyf and a contracted Llan-lwy.
Toponymists dismiss both Teilo and Eloi in favour of Tylwyf, but he is not a recognised saint. [Deric John, Nov 2006]