Iori is a personal name in Japanese and in Welsh (where it is a diminutive of Iorwerth).
He was a grandson of Hywel ap Siencyn ab Iorwerth (d. 1494) of Ynysymaengwyn and was vicar of St Cadfan's Church in Tywyn between 1555 and his death in 1570.
It is from the youngest of these sons, Iorwerth ab Owain ap Madog ap Maredudd, that the barons of Cymmer yn Edeyrnion claim descent.
Iorwerth was apportioned the commotes of Arfon and Arllechwedd, with his seat at Dolwyddelan, with Maelgwn retaining Ynys Môn, and with Cynan receiving Meirionydd.