[5][n 3] Manchan probably died of famine during volcanic winters caused by the extreme weather events of 535–536, which preceded the 6th century Justinian plague of Mohill.

[34] John Colgan decided "that for want of authentic documents to prove the contrary, he must consider them as different persons" as feasts and chronologies disagree.

[37] On the authority of Colgan, and the scribes of Iona Abbey who recorded his death as 538 AD in the Annals of Tigernach, Manchán of Mohill must be considered a distinct "Manchan",[16][38] born in Ireland or Wales and flourishing c. 464 – c. 538.

[39] He belonged to the "first order of Patrician clergy", active missionary priests accompanying or following Saint Patrick, typically Britons or Irish ordained by him and his successors.

[10][30][52][n 9] Persons of this name from Wales include Meugan (Maucan or Moucan) mentioned in the "11th-century life of Cadoc" of Llancarfan in Glamorganshire,[54][55] and Mannacus of Holyhead whose feast day falls on 14 October.

In county Leitrim, Manchán is venerated as patron saint of Mohill-Manchan parish since the foundation of the Monastery of Maothail-Manachan and the Justinian plague of Mohill.

John O'Donovan visiting 19th century Mohill, claimed "Monahan's (or St. Manchan's) Well is still shown there",[3] though the location of his holy well is forgotten.

The plot of the acclaimed novel by John McGahern, titled "Amongst Women", revolves around "Monaghan day" in Mohill, county Leitrim.

[85] In the 12th century, "Ruaidrí Ua Conchobair commenced his reign by creating shrines for the relics of St. Manchan of Moethail" and Saint Comman of Roscommon.

[90][94] The reincarnation of centuries-old Irish metalworking techniques, such as the juxtaposition of red and yellow enamel, is seen on the shrine, and the Cross of Cong.

[95] Before the Vikings there were already varied ethnic types in Ireland, and a long disappearing "Mediterranean" stratum of architecture and costume identifiable as "Iberian" is evidenced by the Shrine of Manchan and the Book of Kells.

[98] In 1861, an "appliqué" figure of gilt, cast copper-alloy, 13.7cm high, 2.75cm wide, and 1.7 cm thickness, was reportedly found at the grave-yard of Clonmacnoise, and presented with a short beard and moustache, a pointed decorated hat covering his ears, hands flat on his bare chest, with a pleated decorated kilt, one missing leg, and was very similar those remaining on the shrine of Manchan, so is assumed to have fallen off.

[99] Margaret Stokes claimed a robed figurine holding a book, found buried near Saint John's Abbey at Thomas Street, Dublin, bears resemblance to the Manchan shrine figures, but "of much finer workmanship and evidently earlier date", but unfortunately she fails to expand further.

[105] The technical and stylistic similarities to the "Cross of Cong group",[a 2] confirms without doubt the shrine of Manchan was crafted at the "well-defined and original" fine-metal workshop active in twelfth century county Roscommon.

[92][94][106][107][108][109][110][111][112] The shrine was likely commissioned by Bishop "Domnall mac Flannacain Ui Dubthaig", of Elphin,[113] one of the richest episcopal see's in Medieval Ireland,[110] and created by the master gold-craftsman named Irish: Mael Isu Bratain Ui Echach ("Mailisa MacEgan"), whom John O'Donovan believed was Abbot of Cloncraff in county Roscommon,[114][110] though firm evidence for this identification is lacking.

[56][113][121] Confused folklore credits Mohill priests saving the shrine from iconoclasts by fleeing the Monastery of Mohill-Manchan to County Offaly- The association with Clonmacnoise and Clonfert might also be strong as the smaller heads on the shrine (figurines dated 13th century) are considered similar to those "on the underside of the abaci of the chancel arch at the Nun's church, Clonmacnoise, and the portal at clonfert".

608, a member of Canons Regular of Augustinian, patron of seven churches, and granted various glebes, lands, fiefs, and tithe to the Monastery of Mohill-Manchan since 608.

[42][14][126] However, there was no such thing as Canons Regular order of Augustinian, glebes, tithes back in the 5th–7th centuries, so these contemporary concepts would not illuminate the life of any Saint Manchan.