[6] He is described as the son of Ithel Hael, who came to Britain from Armorica (present-day northern France) towards the end of the 5th century.

[3] After some repairs in the early part of the 19th century, St Fflewin's was partially rebuilt ("judiciously", says a 2009 guide to the buildings of north-west Wales)[9][note 3] in 1864 and further restored during the 1930s.

[3][5] The Welsh poet and clergyman Morris Williams (better known by his bardic name "Nicander") was rector here from 1859 until his death in 1874; he was buried at Llanrhuddlad, one of the other Anglesey churches for which he had responsibility.

The sill of the window has a fragment of a medieval gravestone (dating from some time after 1300) set into it, inscribed HIC IACET MADOCUS.

[13] The church has national recognition and statutory protection from alteration as it has been designated by Cadw (on behalf of the National Assembly for Wales) as a Grade II listed building – the lowest of the three grades of listing, designating "buildings of special interest, which warrant every effort being made to preserve them".

Cadw also notes that it retains "the vernacular character of a pre gothic revival church".

[3] Samuel Lewis said that the church, which he described as "a plain edifice", was "beautifully situated near a small lake, and surrounded with pleasing scenery".

He said that the church "has been so completely modernised, that it is doubtful whether any original feature remains but the bell-gable and one single light window in the north wall".