Yet the site carries a legend that reaches into one of the great navigational myths of the early Christian world. Some authorities have attributed the foundation to a St Baronthus, said to have been a contemporary of St Brendan (484–577), and to have been the very person who fired Brendan's imagination for his famous voyage by describing the travels of his own son, Mernoc, in search of a mystical Land of Promise. Whether Baronthus was a historical figure or a figure of folklore is a question the ruins cannot answer, and one earlier commentator noted, with dry candour, that sceptics need not feel apologetic.

The documentary record begins more solidly in 1302, when the papal taxation of the Deanery of Offeria in the diocese of Ardfert listed the church of 'Barun' as valued annually at ten shillings, with its tithe at twelve pence. Through the fifteenth and early sixteenth centuries the vicarage passed through a succession of named incumbents. In 1464 a Hubert Stundon was associated with the parish church then recorded as 'Rindbeara'. By 1473 Stundon had resigned and the vicarage, recorded under the alias 'Aglasnalanday', passed to David FitzMaurice. In 1477 John FitzMaurice was appointed to the church of 'Baron', and by 1505 an Edmund FitzMaurice appears in connection with the parish under yet another variant name, 'Aglaysnalany alias Keynucare'. The shifting spellings across these entries reflect the ordinary chaos of medieval Latin record-keeping rather than any change to the place itself. The physical remains, described in detail in 1989, include a compound attached to the north wall of the church, its side walls extending some 16.76 metres from the gables, which may have housed the priest's dwelling or served as an additional burial enclosure. Human bones turned up during ploughing on the south side at some unrecorded point in the past, and part of the ground was used as a children's burial ground, a cillín, within living memory of the 1989 account. A cillín was an informal burial ground, typically used for unbaptised infants and others excluded from consecrated ground, and their presence beside ruined churches is common across rural Ireland, though seldom well documented.