Irish royal families

Significant kingdoms known from early historical times (2nd–7th centuries) included Eóganachta, Corcu Loígde, Connachta, Uí Fiachrach, Breifne, Aileach, Airgíalla, Dál Riata, Ultonia, Brega, Mide, Laigin, Osraige, Laois, Muma, Iarmuman, Desmumu, Tuadmumu, Hy Many.

In several cases they claimed utterly different racial backgrounds from neighbours, Ireland being home to "races" such as the Delbhna, Conmaicne Mara, Cruithne, Eóganachta or Deirgtine, Érainn, Fir Bolg, Grecraighe, Laigin, Ulaid, Mairtine, Dáirine, and a host of others.

Some families successfully made the transition from kingdoms to earldoms or lordships – with the same ruling dynasty – into the 17th century and beyond, taking their seats in the Irish House of Lords.

By 1700 all had long been brought fully and firmly under the dominion of English rule, though local feeling for each area as a distinct entity lasted as least as late as the Great Famine.

Many went into exile for educational or professional advancement (often in the military), while for those remaining the penal laws, especially relating to inheritance, over time meant many conformed to the Established Church and English culture to retain their land or risk losing it to family members who did.