Background
He was the son of Connor O"Brien and his wife Maire Rua McMahon.
He was the son of Connor O"Brien and his wife Maire Rua McMahon.
In 1692, O"Brien entered the Irish House of Commons, sitting for Clare until 1714. Lucius was the father of Sir Edward O"Brien, 2nd Baronet. When Murrough O"Brien, 1st Earl of Inchiquin was captured Lady Inchiquin petitioned for her husband"s release but Sir Donough O"Brien wrote that she had no mind to see any of his relations "for his being a papist".