Words and Proper Names

áoi trasgartha (or trasgairthe)

Hoyne (Mícheál): Early Modern Irish miscellanea: 3. Áoi trasgartha.
In Ériu 67 (2017), pp. 178–183.
On the distinction of words earlier written with ai (which later became oi but did not retain a variant in ai) and also with (later written áoi), responsible for various metrical licences.