João O'Neill (in Irish Seán Ó Néill, in English Shane/John O'Neill) (Ireland, Ulster, Archbishopric of Armagh, County Tyrone, Richhill Village, Parish of Kilmore - Lisbon, Santos-o-Velho, 21 January 1788), was the titular head of a branch of the Clanaboy O'Neill dynasty, whose family has been in Portugal since the 18th century.
João O'Neill Wikipedia
He was the first-born son of the previous head Conn (Constantine) O'Neill and wife Cecilia O'Hanlon.
In 1740, for religious and political motives, he passed to Portugal (with his brothers), where he was an important Proprietor in the Council of Almada (and here he acquired the House and Farm of Arealva).
He married in Lisbon, São Paulo, on 2 September 1750 to Valentina Maria Josefa Ferreira (Torres Vedras, Carmões, 14 February 1730 - ?), daughter of José Ferreira (Lisbon, São Miguel de Alfama - ?), and wife Maria Ferreira (Torres Vedras, Carmões - ?), and had three children:Carlos O'Neill (Lisbon, Santa Catarina, 9 June 1760 - 24 June 1835)
Cecília O'Neill, Prioress at the Catholic Convent of the Irish Sisters of o Bom Sucesso, in Lisbon
Ana O'Neill, Prioress at the Catholic Convent of the Irish Sisters of o Bom Sucesso, in Lisbon, following her sister