[1] Manchán twice makes his appearance in Latin sources as a scholar whose authority still mattered after his death.
First, he is probably the Manchianus, called pater and sapiens, who is named by an anonymous Irishman in his preface to the De mirabilibus sacrae scripturae ('On the miraculous things in sacred scripture'), written in 655 and so shortly after Manchán's death.
[1][2] The author, who uses the nom de plume Augustine and is for this reason known today as the Irish Pseudo-Augustine, appears to have been a pupil of Manchán as well as of one Eusebius.
This anonymous work is uniquely preserved in a manuscript now held at Karlsruhe (Germany), but once in the possession of Reichenau Abbey.
[3] The Manchín feast day commemorated on 2 January in Irish martyrologies probably identifies him,[1] with this feast day shared by the likely identical Manchan of Coolcashin,[3] and the contemporary Mainchín of Luimnech, whose festival is otherwise recorded on 29 December.