- A junior branch of the Massys of Duntrileague, county Limerick, descended from the Reverend Godfrey Massy of Mount Sion, county Limerick and Vicar of Dysart and Prebendery of Limerick. In 1819 George Massy of Glenwilliam married as his second wife Eliza Odell of the Grove, county Limerick. She married secondly Daniel Power. The Glenwilliam estate and the lands of Gortroe amounting to 942 acres belonging to George Thomas De Massy, a minor, were advertised for sale in June 1851. Sales of other lands continued to be advertised in the following years, including land in the barony of Orrery and Kilmore, county Cork in November 1857. Glenwilliam was bought by Edward Atkinson some time in the 1850s. At the time of Griffith's Valuation the Massy estate in the parishes of Ballingarry and Croom was in the hands of the Court of Chancery. George Rollo Massy, a younger son of George and Eliza Massy, held land in th parish of Kilfinnane, barony of Coshlea, at the time of Griffith's Valuation and in the 1870s he owned 1,000 acres in county Limerick. His address was Usher's Quay, Dublin. In July 1866 and July 1875 lands at Ballinanima (178 acres), barony of Coshlea, the estate of George Rollo Massy were advertised for sale. A Mr. Sharp purchased some of these lands in trust in July 1866. A further sale of George Rollo Massey's property was advertised in the Land Judges' Court in November 1888.
- According to Burke's Landed Gentry the Atkinsons settled in the north of Ireland in the late 16th century. Some time in the late 1850s Edward Atkinson of Glenwilliam and Skea House, Enniskillen, county Fermanagh, appears to have bought the Glenwilliam estate from the Massys [or possibly won it in a game of cards, see Bence Jones]. In the 1870s Edward Atkinson of Glenwilliam Castle, Ballingarry, county Limerick, owned 2,655 acres in the county. He was the father of John Atkinson, Attorney General of Ireland in the 1890s and Member of Parliament for North Derry and later created Lord Atkinson.