| Royal Title: | Kings |
| Realm: | Leinster |
| Native Name: | Rí Laighin |
| Coatofarms: | Kingdom of Leinster-900.svg |
| Coatofarmssize: | 250px |
| Coatofarmscaption: | Map of Leinster, c. 10th century. |
| First Monarch: | Úgaine Mór |
| Last Monarch: | Domhnall Spáinneach Mac Murchadha Caomhánach |
| Style: | Rí Laighin |
| Residence: | Dún Ailinne |
| Appointer: | Tanistry |
| Began: | Ancient |
| Ended: | 1603 or 1632 (de facto) |
The kings of Leinster (Irish: Rí Laighín) ruled from the establishment of Leinster during the Irish Iron Age until the 17th century Early Modern Ireland. According to Gaelic traditional history found in works such as the Book of Invasions, Leinster was created during the division of Ireland among the Irish Gaels, descendants of Milesius: Leinster was one of the territories held by the offspring of Heremon. In the 7th century BC, the branch of the Heremonians who would establish Leinster, starting with Úgaine Mór, were also High Kings of Ireland and Kings of Tara. Their ascent to hegemony in Ireland was associated with the decline in influence of their Ulster-based Heremonian kinsmen from the Érainn.
Apart from Úgaine Mór, other prominent Kings of Leinster from this period who were also High Kings of Ireland were Labraid Loingsech and Cathair Mór. A mythology developed that Labraid Loingsech had horses ears: he spent some time exiled in Transalpine Gaul (dated roughly to the period of the Roman–Gallic wars) where his grandmother was from and returned to Ireland with Gaullish mercenaries. He established a base in the area, which was renamed from "Gailian" to Leinster, in reference to the pointed-spears held by the Gaullish Gaesatae mercenaries who provided the backbone of Labraid Loingsech's powerbase and brought him to the High Kingship. Cathair Mór, who was also a High King of Ireland, is perhaps the most important figure genealogically in Leinster as all of the subsequent kinship groups which ruled Gaelic Leinster claimed descent and legitimacy to rule from one of his ten sons who had offspring.
By the time of Early Christian Ireland, the Laighín had lost their grip on Irish hegemony with the rise of the descendants of Conn of the Hundred Battles (the Connachta and the Uí Néill). The latter pushed down into Leinster and created the Kingdom of Meath based at Uisnech, under the Southern Uí Néill from territories belonging to the Kingdom of Leinster and to the west Osraige was taken from the Laighín by the Corcu Loígde of Munster.
During the 5th to the early 8th centuries, the Kingship of Leinster was contested by various different branches of the Laighín, including the Uí Cheinnselaig (ancestors of the Mac Murchada and Caomhánach), the Uí Dúnlainge (ancestors of the O'Byrnes and the O'Tooles), the Uí Bairrche (ancestors of the Mac Gormáin), the Uí Máil (ancestors of the Ó Conchobhair Uí Failghe) and others.
From the 8th until the 11th century, the kingship of Leinster rotated in a remarkably stable arrangement between three branches of the North Leinster Uí Dúnlainge kinship, namelt the Uí Fáeláin (ancestors of the O'Byrnes), the Uí Muiredaig (ancestors of the O'Tooles) and the Uí Dúnchada (whose descendants became the MacGillaMoCholmóc and later the FitzDermots). In the 9th century, the Laighín also regained control of Osraige but it remained a largely independent realm under the Mac Giolla Phádrag, from the semi-autonomous Uí Failghe kinship group.
The Uí Cheinnselaig in South Leinster took back control of the kingship of Leinster in the 11th century, with Diarmait mac Máel na mBó, who became the first Leinsterman to be High King of Ireland in over a thousand years and claimed to the most senior line of the Laighín. An enemy of the Vikings of Dublin, he gave refuge to the sons of Harold Godwinson after the Normans conquered England. It is from this line that the Mac Murchada family originate and later Diarmait Mac Murchada would be implicated in the 12th century Norman invasion of Ireland after he tried to win back his Leinster throne. The reigning dynasty adopted the surname Caomhánach (Kavanagh) and continued to rule a rump Kingdom of Leinster until the early 17th century, with the last recorded King of Leinster being Domhnall Spáinneach Mac Murchadha Caomhánach. Throughout the centuries after the Norman invasion, several Kings and also leaders from dynasties who had previously held the Kingship of Leinster, continued to resist the invasion and hounded the English Pale periodically from the Wicklow Mountains: including the leaders of the O'Toole and O'Byrne clans (notable examples include Art Óg Mac Murchadha Caomhánach and Fiach McHugh O'Byrne) until the 17th century.
See main article: article, Laigin and Kingship of Tara. |-| Úgaine Mór
634–594 BC
|| || Son of Eochu Buadach||unknown || 594 BCE|-| Lóegaire Lorc
594–592 BC
|| || Son of Úgaine Mór||unknown || 592 BCE|-| Ailill Áine
592–592 BC
|| || Son of Lóegaire Lorc||unknown || 592 BCE|-| Cobthach Cóel Breg
592–542 BC
|| || Son of Úgaine Mór||unknown || 542 BCE|-| Labraid Loingsech
542–523 BC
|| || Son of Ailill Áine mac Lóegaire Lorc||unknown || 523 BCE|-| Cathair Mór
119–122 AD
|| || Son of Fedlimid Fir Urglais mac Cormaic Gealtach||11 children || 122 AD|-|}
See main article: article and Uí Cheinnselaig. |-| Fiacha Baicheda mac Cathair Mór
–
|| || Son of Cathair Mór ||unknown || 416|-| Bressal Bélach mac Fiacha Baicheda
–436
|| || Son of Fiacha Baicheda mac Cathair Mór ||unknown || 436|-| Énnae Cennsalach mac Labhradh
–
|| || Son of Labhradh mac Bressal Bélach ||unknown || unknown|-|}
See main article: article and Uí Bairrche. |-| Muiredach Mo Sníthech mac Dáire Barrach
–
(claimant) || || Son of Dáire Barrach mac Cathair Mór ||unknown || unknown|-| Móenach mac Muiredach Mo Sníthech
–
(claimant) || || Son of Muiredach Mo Sníthech mac Dáire Barrach ||unknown || unknown|-|}
See main article: article and Uí Enechglaiss. |-| Mac Cairthinn mac Coelboth
–446
|| unknown || Son of Cóelbad ||unknown || 446|-|}
|-| Crimthann mac Énnai
446–483
|| || Son of Énnae Cennsalach ||unknown || 483|-|}
See main article: article and Uí Garrchon. |-| Fincath mac Garrchu
483–485
|| unknown || Son of Garrchú mac Fothaid ||unknown || 485|-| Fráech mac Finchada
485–495
|| unknown || Son of Fincath mac Garrchu ||unknown || 495|-|}
See main article: article and Uí Dúnlainge. |-| Ailill mac Dúnlainge
495–527
|| || Son of Dúnlaing mac Énda Niada ||Etromma Ui Tellain || 527|-| Cormac mac Ailillo
527–535
|| || Son of Ailill mac Dúnlainge ||unknown || 535|-| Coirpre mac Cormaic
535–546
|| || Son of Cormac mac Ailillo ||unknown || 546|-| Colmán Már mac Coirpre
546–576
|| || Son of Coirpre mac Cormaic ||unknown || 576|-| Áed Dub mac Colmáin
576–592
|| || Son of Colmán Már mac Coirpre ||unknown || 639|-|}
See main article: article and Uí Máil. |-| Áed Dibchine
592–595
|| || Son of Seanach Diodhach mac Carthann Muadh ||unknown || 595|-|}
|-| Brandub mac Echach
595–605
|| || Son of Echu mac Muiredaig ||unknown || 605|-| Rónán mac Colmáin
605–624
|| || Son of Colmán mac Cormaic ||unknown || 624|-|}
|-| Crimthann mac Áedo
624–633
|| || Son of Áed Dibchine ||unknown || 633|-|}
|-| Fáelán mac Colmáin
633–656
656–666
|| || Son of Colmán Már mac Coirpri ||unknown || 666|-|}
|-| Crundmáel Erbuilc
656
|| || Son of Rónán mac Colmáin ||unknown || 656|-|}
|-| Fiannamail mac Máele Tuile
666–680
|| || Son of Máele Tuile mac Rónán Crach ||unknown || 680|-|}
|-| Bran Mut mac Conaill
680–693
|| || Son of Conall mac Fáelán ||unknown || 693|-|}
|-| Cellach Cualann
693–715
|| || Son of Gertighe mac Diocolla Dana ||unknown || 715|-|}
|-| Murchad mac Brain Mut
715–727
|| || Son of Bran Mut mac Conaill ||unknown || 727|-| Dúnchad mac Murchada
727–728
|| || Son of Murchad mac Brain Mut ||unknown || 728|-|}
See main article: article, Ó Broin and O'Byrne family. |-| Fáelán mac Murchada
728–738
|| || Son of Murchad mac Brain Mut ||unknown || 738|-|}
|-| Bran Becc mac Murchada
738
|| || Son of Murchad mac Brain Mut ||unknown || 738|-|}
|-| Áed mac Colggen
738
|| || Son of Colcú mac Bressail ||unknown || 738|-|}
See main article: article and Ó Tuathail. |-| Muiredach mac Murchada
738–760
|| || Son of Murchad mac Brain Mut ||unknown || 760|-|}
See main article: article and Uí Dúnchada. |-| Cellach mac Dúnchada
760–776
|| unknown || Son of Dúnchad mac Murchada ||unknown || 776|-|}
|-| Ruaidrí mac Fáeláin
776–785
|| || Son of Fáelán mac Murchada ||unknown || 785|-|}
|-| Bran Ardchenn
785–795
|| || Son of Muiredach mac Murchada ||unknown || 795|-|}
|-| Fínsnechta Cethardec
795–808
|| unknown || Son of Cellach mac Dúnchada ||unknown || 808|-|}
|-| Muiredach mac Brain
808–818
|| || Son of Bran Ardchenn ||unknown || 818|-|}
|-| Muiredach mac Ruadrach
818–829
|| || Son of Ruaidrí mac Fáeláin ||unknown || 829|-|}
|-| Cellach mac Brain
829–834
|| || Son of Bran Ardchenn ||unknown || 834|-|}
|-| Bran mac Fáeláin
834–838
|| unknown || Son of Fáelán mac Cellaig ||unknown || 838|-|}
|-| Lorcán mac Cellaig
838–851
|| || Son of Cellach mac Brain ||unknown || unknown|-| Túathal mac Máele-Brigte
851–854
|| || Son of Muiredach mac Brain ||unknown || 854|-|}
|-| Ruarc mac Brain
854–862
|| unknown || Son of Bran mac Fáeláin ||unknown || 862|-|}
|-| Muirecán mac Diarmata
862–863
|| || Son of Diarmata mac Ruadrach ||unknown || 863|-|}
|-| Dúnlaing mac Muiredaig
863–869
|| || Son of Muiredach mac Brain ||unknown || 869|-| Ailill mac Dúnlainge
869–871
|| || Son of Dúnlaing mac Muiredaig ||unknown || 871|-|}
|-| Domnall mac Muirecáin
871–884
|| || Son of Muirecán mac Diarmata ||unknown || 884|-|}
|-| Muiredach mac Brain
884–885
|| unknown || Son of Bran mac Fáeláin ||unknown || 885|-|}
|-| Cerball mac Muirecáin
885–909
|| || Son of Muirecán mac Diarmata ||unknown || 909|-|}
|-| Augaire mac Aililla
909–917
|| || Son of Ailill mac Dúnlainge ||unknown || 917|-|}
|-| Faelan mac Muiredach
917–942
|| unknown || Son of Muiredach mac Brain ||unknown || 942|-| Lorcán mac Fáelán
942–943
|| unknown || Son of Faelan mac Muiredach ||unknown || 943|-|}
|-| Bran Fionn mac Máel Mórda
943–947
|| || Son of Máel Mórda mac Murchada ||unknown || 947|-|}
|-| Túathal mac Úgaire
947–958
|| || Son of Augaire mac Aililla ||unknown || 958|-|}
|-| Cellach mac Faelan
958–966
|| unknown || Son of Faelan mac Muiredach ||unknown || 966|-|}
|-| Murchad mac Brain Fionn
966–972
|| || Son of Bran Fionn mac Máel Mórda ||unknown || 972|-|}
|-| Úgaire mac Túathail
972–978
|| || Son of Túathal mac Úgaire ||unknown || 978|-|}
|-| Domnall Claen
978–984
|| unknown || Son of Lorcán mac Fáelán ||unknown || 984|-| Donnchad mac Domnall Claen
984–1003
|| unknown || Son of Domnall Claen ||unknown || unknown |-|}
|-| Máel Mórda mac Murchada
1003–1014
|| || Son of Murchad mac Brain Fionn ||unknown || 1014|-|}
|-| Dúnlaing mac Tuathal
1014
|| || Son of Túathal mac Úgaire ||unknown || 1014|-| Donncuan mac Dúnlainge
1014–1016
|| || Son of Dúnlaing mac Tuathal ||unknown || 1016|-|}
|-| Bran mac Máel Mórda
1016–1018
|| || Son of Máel Mórda mac Murchada ||unknown || 1052|-|}
|-| Augaire mac Dúnlainge
1018–1024
|| || Son of Dúnlaing mac Tuathal ||unknown || 1024|-| Donnchad mac Dúnlainge
1024–1033
|| || Son of Dúnlaing mac Tuathal ||unknown || unknown|-|}
See main article: article, Mac Giolla Phádraig and Dál Birn. |-| Donnchad mac Gilla Pátraic
1033–1039
|| || Son of Gilla Pátraic mac Donnchada ||unknown || 1039|-|}
|-| Murchad mac Dúnlainge
1039–1042
|| || Son of Dúnlaing mac Tuathal ||unknown || 1042|-|}
|-| Diarmait mac Máel na mBó
1042–1072
|| || Son of Donnchad Máel na mBó || Derbforgaill, daughter of Donnchad mac Briain || 7 February 1072|-| Murchad mac Diarmata
1052–1070
|| || Son of Diarmait mac Máel na mBó ||unknown || 1070|-| Domnall mac Murchada
1072–1075
|| || Son of Murchad mac Diarmata ||unknown || 1075|-| Donnchad mac Domnaill Remair
1075–1089
|| || Son of Domnall Remar mac Máel na mBó ||unknown || 1089|-| Énna mac Diarmata
1089–1092
|| || Son of Diarmait mac Máel na mBó ||unknown || 1092|-| Diarmait mac Énna
1092–1098
|| || Son of Énna mac Diarmata ||unknown || 1098|-| Donnchadh mac Murchada
1098–1115
|| || Son of Murchad mac Diarmata ||unknown || 1115|-|}
See main article: article and Uí Failghe. |-| Conchobar mac Congalaig
1115
|| || Son of Congalach Ua Conchobair||unknown || 1115|-
|}
|-| Diarmait mac Énna meic Murchada
1115–1117
|| || Son of Énna Mac Murchada ||unknown || 1117|-| Énna mac Donnchada mic Murchada
1117–1126
|| || Son of Donnchadh mac Murchada ||unknown || 1126|-| Diarmait Mac Murchada
1126–1166
1169–1171
|| || Son of Donnchad mac Murchada ||unknown || 1171|-|}
See main article: article and Caomhánach. |-| Domhnall Caomhánach Mac Murchada
1171–1175
|| || Son of Diarmait Mac Murchada ||unknown || 1175|-| Domhnall Óg mac Domhnall Caomhánach
–
|| || Son of Domhnall Caomhánach Mac Murchada ||unknown || unknown |-| Muirchertach mac Domhnall Óg Mac Murchada Caomhánach
–1282
|| || Son of Domhnall Óg mac Domhnall Caomhánach ||unknown || 1282|-| Muiris mac Muirchertach Mac Murchada Caomhánach
1282–1314
|| || Son of Muirchertach mac Domhnall Óg Mac Murchada Caomhánach ||unknown || 1314|-| Art Mac Murchada Caomhánach
1314–1323
|| || Son of Domhnall Óg mac Domhnall Caomhánach ||unknown || 1361|-| Domhnall mac Art Mac Murchada Caomhánach
1323–1338
|| || Son of Art mac Domhnall Óg Mac Murchada Caomhánach ||unknown || 1338|-| Domhnall mac Domhnall Mac Murchada Caomhánach
1338–1347
|| || Son of Domhnall mac Art Mac Murchada Caomhánach ||unknown || 1338|-| Muirchertach mac Muiris Mac Murchada Caomhánach
1347–1354
|| || Son of Muiris mac Muirchertach Mac Murchada Caomhánach ||unknown || 1354|-| Art Mór Mac Murchada Caomhánach
1354–1362
|| || Son of Muirchertach mac Muiris Mac Murchada Caomhánach ||unknown || 1362|-| Diarmait Mac Murchada Caomhánach
1362–1369
|| || Son of Domhnall mac Domhnall Mac Murchada Caomhánach ||unknown || 1369|-| Donnchadh mac Muirchertach Mac Murchada Caomhánach
1369–1375
|| || Son of Muirchertach mac Muiris Mac Murchada Caomhánach ||unknown || 1375|-| Art Mór Mac Murchadha Caomhánach
1369–1375
|| || Son of Muirchertach mac Muiris Mac Murchada Caomhánach ||unknown || 1375|-| Art Óg Mac Murchadha Caomhánach
1375–1417
|| || Son of Art Mór Mac Murchadha Caomhánach ||unknown || 1417|-| Donnchadh mac Art Mac Murchadha Caomhánach
1417–1478
|| || Son of Art Óg Mac Murchadha Caomhánach ||unknown || 1478|-| Domhnall Riabhach Mac Murchadha Caomhánach
1478
|| || Son of Gerald Mac Murchadha Caomhánach ||unknown || 1478|-| Muircheartach mac Donnchadh Mac Murchadha Caomhánach
1478–1512
|| || Son of Donnchadh mac Art Mac Murchadha Caomhánach ||unknown || 1512|-| Art Buidhe Mac Murchadha Caomhánach
1512–1517
|| || Son of Domhnall Riabhach Mac Murchadha Caomhánach ||unknown || 1517|-| Gerald Mac Murchadha Caomhánach
1517–1523
|| || Son of Domhnall Riabhach Mac Murchadha Caomhánach ||unknown || 1523|-| Muiris mac Domhnall Riabhach Mac Murchadha Caomhánach
1523–1531
|| || Son of Domhnall Riabhach Mac Murchadha Caomhánach ||unknown || 1531|-| Muircheartach mac Art Buidhe Mac Murchadha Caomhánach
1531–1547
|| || Son of Art Buidhe Mac Murchadha Caomhánach ||unknown || 1547|-| Muiris mac Domhnall Riabhach Mac Murchadha Caomhánach
1523–1531
|| || Son of Domhnall Riabhach Mac Murchadha Caomhánach ||unknown || 1531|-| Murchadh Mac Murchadha Caomhánach
1531–1557
|| || Son of Muiris mac Domhnall Riabhach Mac Murchadha Caomhánach ||unknown || 1531|-| Criomthann Mac Murchadha Caomhánach
1557–1582
|| || Son of Murchadh Mac Murchadha Caomhánach ||unknown || 1582|-| Domhnall Spáinneach Mac Murchadha Caomhánach
1582–1603
|| || Son of Donnchadh mac Cathaoir Mac Murchadha Caomhánach ||unknown || 1632|-|}