Charles-Edwards suggests that the site may have belonged originally to the province of Leinster rather than Mide, but that the political geography had changed by the 8th century, when much of southern Brega was divided between different septs of the Síl nÁedo Sláine.

By that time, Domnach Sechnaill lay in the kingdom of the Uí Chernaig, close to the royal crannóg seat in Loch nGabor, as did the churches of Trevet and Kilbrew.

His name was borrowed into the vernacular as Sechnall, according to a pattern for which David N. Dumville proposes the following stages of development: Secundinus > *Sechundinus > *Sechundīnəs > *Sechundīn > *Sechndən > *Sechnən and finally by the 8/9th century, > *Sechnəl.

The ascription to Secundinus, whether true or false, is commonplace in medieval sources, occurring as early as in the Félire Óengusso,[7] and notably appears in the Irish preface preserved in some manuscript copies of the Hymn.

[8] Srúaim n-ecnai co n-áni,Sechnall mind ar flathae,ro gab ceol, sóer solad,molad Pátric Machae.

It states that Secundinus was a son of Restitutus and St Patrick's sister Dar Ercae; in the Chronicon Scotorum the latter is named Culmana.

[3][11] The preface cites a stanza by Armagh scholar Eochaid ua Flannacain (d. 1005) to assert that Restitutus belonged to the Lombards of Letha, a place-name which referred to Gaul but was sometimes confused with Latium.

[12] In 441 Palladius was recalled to Rome to be examined by the newly elected Pope Leo I, leaving Secundinus in charge of the Church in Ireland.