Padraig Mac Giolla-Domhnaigh

Monks—In the County and City of Dublin, and those parts mostly included in the old English Pale, the name Monks is the direct anglicised form of Monaghan (O'Manachain).

Alphabetical Index of Anglicised Surnames in Ireland

See also Woulfe’s Irish Names and Surnames
and O'Hart's Irish Pedigrees