Mac Aodhagáin

Mac Aodhagáin (English: Egan or Keegan), is an Irish Gaelic clan of Brehons who were hereditary lawyers - firstly to the Ó Conchobhair Kings of Connacht, and later to the Burkes of Clanricarde.
The earliest surviving Irish law manuscript, "In Senchas Már", was written prior to 1350 at a school (patronised by the Mac Aodhagáin) at Duniry, near Loughrea. Other branches of the clann maintained schools at Park, outside Tuam, and at Ballymacegan in Co. Tipperary. The work known as Leabhar Breac was produced by one of their students, while Dubhaltach MacFhirbhisigh may have studied at Ballymacegan under Flann Mac Aodhagáin up to the year 1643.
Naming conventions.
The surname has been Anglicised in a variety of ways, including as Mac Egan, Egan, Eagan, Keegan, McKeegan, or Keigan, McKiegan, and McKagan.
Family trees from "Geinealaigh Clainne Aodhagáin", below.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 | | |
 Mac Aodhagáin Mac Aodhagáin of Connacht, Magnus
 of Munster Westmeath and Leinster |
 Aed
 |
 Domnall
 |
 Aed Gilla Ísa
Mac Aodhagáin of Munster.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 |_____________________________________________________________
 | | |
 Gilla na Naem Fland Fingin
 |__________________ | |
 | | Saérbrethach Fingin
 Saérbrethach Dond Sléibhe | |
 | | Mael Isu Ruadh, Saerdalach
 | | d. 1317.
 Fland Gilla na Naem
 | |_________________________
 Tomás | | |
 | Conchobar Cairbre Fiachra
 Tomás Aimréid |
 | |_______________________________________________________________________
 Conchobar | | | |
 | Gilla na Naem, d. 1399. Aed, d. 1359. Tadcc Donall, d. 1413.
 Cairbre |______________________________________________ |
 | | | | Conchobar
 Gilla na Naem, d. 1443. Aed Domnall Donnchad _____________|_____________________________
 _________________| ______________________|________________ | | |
 | | | | | | | Sean Tadcc Baethgalach
 Gilla na Naem Cairbre Aed Fergal Conchobar Muirchertach Eogan | |_________
 | | | ___________________________|_______________________ | |
 Domnall Donnchad Domnall, d. 1529. | | | | | Domnall Tacc,
 | &amp; William | | | | | | Aed Clerech,
 | Brian An Cosnamach Conchobar Muircheartach Gilla na Naem | William.
 An Cosnamaid |
 | __________|
 Cairbre | |
 | Cairbre Baethgalach
 |_____________________________________
 | | | |
 William Flann Donnchad Cairbre Óge
 | d. 1643 d. 1602 d. 1601
 Seán, fl. 1644.
Mac Aodhagáin of Lower Connacht.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 | | |
 Mac Aodhagáin | Magnus
 of Munster |
 ________________________|_________
 | | |
 Baethgalach Diarmait Donnchad Claen
 | issue issue
Mac Aodhagáin of Cineil Fiachrach and Offaly.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 | | |
 Mac Aodhagáin | Magnus
 of Munster |
 ________________________|_________
 | | |
 Baethgalach Diarmait Donnchad Claen
 | issue issue
Mac Aodhagáin Ollamhs of Connacht.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 | | |
 Mac Aodhagáin | Magnus
 of Munster |
 ________________________|______________
 | | |
 Baethgalach Diarmait Donnchad Claen
 (see Lower Connacht) |
 |_________________________________________________________________________________
 | |
 Sairbrethach In Cosnamaid
 | |
 Mael Isa Dond, d. 1330. Crimthann
 _______________________|________________________________________________________________ |
 | | | | | | Aed
 Sairbrethach Caech, d. 1354. Roiberd Muirchertach Buidhe Sean Donnchad Tomas Tuathach
 |_________________________ | |____________________
 | | Eogan | |
 Solam Saerdalach Tomaltach Carrach Baethgalach
 | ___________________| |
 | | | Eogan
 | Donnchad Dub Rioberd |
 | | | Eogan
 | | |________________________________
 | | | | |
 | | Brian, d. 1473. Sean Toinn Buidhe
 | | | | |
 | | Aed, Roiberd Solam Buidhe
 | | Magnus.
 | |______________________________________________________________________________________________________________________
 | | | | | | | | | |
 | Brian Carrach Fergal Aed Saerdalach Eogan Gilla na Naem Domnall Clerech Tadcc Diarmait Buidhe
 | | | | |
 | Sean, Conchobar, Uilliam, Tadcc,
 | Uilliam, Saerdalach, Tadcc, Sean.
 | Saerdalach, Muirchertach C., Mael-Ruin,
 | Cormac G., An Cosnamaid, d. 1529. Donnchad,
 | Conchobar. Cairbre.
 | na-Tet
 | an brathair
 |____________________________________________________________________________
 | |
 Airechtach Mael Isu
 | |____________________
 Gilla na Naem, d. 1447. | |
 |________________________________________________________________ Saerbrethach An Cosnamaid Caech
 | | | | | | |
 Tadcc, d.1487. An Cosnmaid Baethgalach Gilla na Naem Oc Fergal Conchobar, Caibre,
 &amp; Aed. William,
 &amp; Tadcc.
Mac Aodhagáin of Breifine and Teathba.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 | | |
 Mac Aodhagáin | Magnus
 of Munster |
 ________________________|_________
 | | |
 Baethgalach Diarmait Donnchad Claen
 of Lower Connacht issue |
 _________________________________|
 | |
 Luccas Mael Simon (see Mac Aodhagáin of Clanricarde)
 |_______________________________________________
 | |
 Tadcc Bacach Brian
 |_______________________________ |_____________________________________________
 | | | | | |
 Brian, Sean, Cormac Roiberd Magnus Solam
 d. 1390. d. 1390. | |
 _______________________________________________| |
 | | | Maine
 Fergal Cormac Sean Sagart
 | _______|____ |
 | | | Muirchertach, d. 1409.
 | Cairbre Cathal Ruad
 |
 |_____________________________________________
 | | | | |
 Eogan Magnus Donnchad Clerech Feidlimid Emann
Mac Aodhagáin of Clanricarde.
 Muirchertach Mac Aodhagáin
 |_______________________________________________
 | | |
 Saérbrethach Donnchad Mór Mael Ísu
 | | |
 Mac Aodhagáin | Magnus
 of Munster |
 ________________________|_________
 | | |
 Baethgalach Diarmait Donnchad Claen
 of Lower Connacht issue |
 _________________________________|
 | |
 Simon Luccas Mael
 |____________________________________________________________________________________________________________________
 | | |
 Sairbrethach Mael Isa Saerdalach
 |_________________________________________________ |_______________________________
 | | | | | |
 Fland Solam In Decanach Aed Raigne Donnchad
 | _______________________| | | |____________ |
 | | | | Diarmait Fland | | Raigne
 | Diarmait William Tadcc Aed Tomaltach |
 | | | | Domnall
 | Diarmait Donnchad Gilla na Naem
 | | |
 | Eogan An Cosnamaid
 | |
 | Conchobar
 Finguine
 |
 Conchobar Ruad, d. 1438.
 |_________________________________________________________________
 | | | | | | |
 Domnall Glas Tadcc William Eogan Gilla na Naem Aed Sean, d. 1487.
 |
 Domnall Oc
 |
 Tadcc
 |
 Tadcc Oc
 |
 Baethgalach