Namely, the Túath where he died was renamed in his honour, and his brother Saint Caillín obtained a substantial honour price in compensation under Brehon Law, securing a revenue stream for the famous monastery of Fenagh.
[2] He belonged to the tribe of Conmaicne-Rein who lived in present-day South Leitrim and West Longford.
Sometime in the 5th or 6th century, Nisi and Caillín journeyed from Ard-Carna Monastery in Roscommon eastwards towards Cora Droma Rúisc crossing the river Shannon to Magh-Cellachain ("the plain of Cellachan"), staying overnight at a place named the Bennachan,[5][n 1] in the home of Cellachan, who was not of the Conmaicne tribe.
[2][8] Nisi's "honour price" became the perpetual claim by the monastic settlement at Fenagh to patronage from Moynish nobles.
[11] Though forgotten today, the place name of Moynish is preserved by the Irish annals and English Fiants.