Mac Fáeláin, Fáelán (c.1125–1203), king of Uí Fáeláin, was the son of Cerball Mac Fáeláin (d. 1127), king of the Kildare kingdom of Uí Fáeláin, and Mór, daughter of Cú Aifne O'Connor Faly (Ó Conchobair Failge) of Offaly. Both Cearball and Fáelán's half-brother Domnall Mac Fáeláin (d. 1141), king of Leinster from 1126, were prominent supporters of Toirrdelbach Ua Conchobair (qv) (d. 1156), high-king of Ireland, making them hated by many of the Leinster nobility. In 1127 Cearball Mac Fáeláin fell defending his daughter's rights as abbess of Kildare against Donnchad Ua Conchobair Failge; his death may have been the cause of unrest launched by the king of Uí Chennselaig, most probably Diarmait Mac Murchada (qv) (MacMurrough) (d. 1171), which Toirrdelbach, probably with the help of Domnall Mac Fáeláin, subdued during 1128. The increased importance of the Meic Fáeláin is revealed in a study of their intermarriage with the other dynasties of west Leinster and the midlands, which further show that relations with Mac Murchada were not always fraught: Mac Murchada married Cerball's daughter Sadb, Fáelán's half-sister, and he avenged Cerball's death by forcibly removing the Ua Conchobair Failge abbess of Kildare in 1132.
While Toirrdelbach Ua Conchobair prospered, the Meic Fáeláin had little to fear, but during the 1130s a series of draining wars exhausted Connacht, and by 1136 Mac Murchada was king of Leinster, having subdued Domnall Mac Fáeláin. That year Uí Fáeláin was scorched by Murchad Ua Máelshechlainn (qv) (d. 1153) in revenge for Mac Murchada's torching of the town of Ardbracken. Mac Murchada ceded suzerainty over Offaly and Uí Fáeláin to Ua Máelshechlainn and pledged to him the service of his army. In effect Uí Fáeláin and its ruling family were traded off to their traditional enemy, which prompted an unsuccessful uprising by the nobility of west Leinster against the Mac Murchada–Ua Máelshechlainn axis in 1138. In 1141 Mac Murchada struck a deadly blow at the Leinster nobility, authorising his brother Murchad Mac Murchada (qv) (d. 1172) to lure Domnall Mac Fáeláin and many others to a meeting, where he slaughtered seventeen of them and blinded many more. The identity of Domnall's successor as king of Uí Fáeláin is not known, though he may have been named Bran. Nothing is known of Fáelán to this point, but in 1150 he probably played a role in the Uí Fáeláin victory over the neighbouring Ó Ciarda (O'Keary) dynasty of Carbury.
In spite of such local successes, the fortunes of Uí Fáeláin and its rulers remained subject to the ambitions of the great powers. In 1153 Muirchertach Mac Lochlainn (qv) (d. 1166) confirmed Maelsechlainn Ua Máelshechlainn (d. 1155) as king of Meath and gave him authority over Offaly and Uí Fáeláin. Mac Lochlainn's victory at Ardee over Ruaidrí Ua Conchobair (qv) (d. 1198), son of Toirrdelbach Ua Conchobair, had profound consequences for Uí Fáeláin: in the aftermath of the battle Mac Murchada romped throughout west Leinster, targeting the loyalists of Ruaidrí, who included the king of Uí Fáeláin, who by now seems to have been Fáelán. The Annals of Tigernach state that Mac Lochlainn killed him, but the Annals of the Four Masters state that he was exiled. As a reward for his service Mac Lochlainn then invested Mac Murchada with Uí Fáeláin and confirmed his kingship over Leinster. Fáelán took refuge at Ruaidrí's court at Tuam, where he received a sympathetic reception. He rose high in Ruaidrí's estimation and became the Connacht king's foremost adviser on Leinster and its politics.
Fáelán remained at Tuam until Ruaidrí chose his moment to invade Leinster, in 1161. With several Leinster exiles, including Fáelán and Máel Sechlainn Ua Conchobair Failge of Offaly, Ruaidrí crossed the Shannon and invaded the midlands, seeking to detach the kingdoms of west Leinster from Mac Murchada's provincial kingdom. After a successful campaign through Meath, he took hostages in Offaly and Uí Fáeláin, but despite these successes Mac Lochlainn forced Ruaidrí to do him homage at Tethbae. Nevertheless the campaign paid off, for both Máel Sechlainn and Fáelán were left as rulers of their kingdoms, perhaps benefiting from an agreement between Ruaidrí and Mac Lochlainn. As the price of their restoration, these princes, even though they were Ua Conchobair clients, were forced to recognise the provincial kingship of Mac Murchada; to secure Fáelán's loyalty Mac Murchada took his son hostage and set the Mac Con Lothair dynasty to keep watch on him.
The blinding of Eochaid Mac Duinn Sléibe of Ulaid, the foster son of Donnchad Ua Cerbaill (qv) of Oriel (Mac Lochlainn's leading vassal), by Mac Lochlainn at Easter 1166 began a chain of events that demolished Mac Murchada's kingship of Leinster. Donnchad repaired to Connacht and gave his allegiance to Ruaidrí, who with Tigernán Ua Ruairc (qv) of Bréifne (d. 1172), and Diarmait Ua Máelshechlainn of Meath, marched to Dublin and was acknowledged there as high-king. After taking Ua Cearbaill's submission at Drogheda, Ruaidrí moved southward to deal with Mac Murchada, Mac Lochlainn's ally. In the face of Ruaidrí's advance Fáelán's tenuous attachment to Mac Murchada quickly dissolved, and he and the Ua Conchobair Failge of Offaly gave hostages to the new high-king. As the invasion of Mac Murchada's heartland of Uí Chennselaig went forward, Mac Murchada submitted to Ruaidrí, signalling the collapse of Mac Lochlainn's power base in Ulster; Ruaidrí's allies closed the net, hunting down and killing Mac Lochlainn in Tyrone.
While Ruaidrí was concentrating on Ulster, Mac Murchada attempted to reassert himself, having encouraged Ó Braenáin (O'Brennan) to kill Mac Gilla Mo Cholmóc, the rebel king of Ui Briúin Chualann. The Ua Conchobair Failge and Fáelán quickly gave pledges to Ruaidrí's lieutenant, Diarmait Ua Máelshechlainn of Meath. With the Dublin Ostmen and Tigernán Ua Ruairc, they marched into Uí Chennselaig. In response Mac Murchada executed Fáelán's son, as well as hostages given him by Domnall Mac Gilla Pátraic (qv) of North Ossory (d. 1185). But at this critical point Mac Murchada's brother Murchad along with the second Uí Fáeláin lord, Murchad Ó Broin, deserted him. Mac Murchada fled, taking ship for England. Uí Chennselaig was divided between Murchad Mac Murchada and one of the Mac Gilla Pátraic kings of Ossory. Before the end of the year Ruaidrí at a meeting at Athlone rewarded all his clients, including Fáelán, who was given a stipend of twelve score cows.
In 1167 Ruaidrí took further steps towards the achievement of effective royal government by presiding over a quasi-national synod at Athboy in Meath, a secular and ecclesiastical convention attended by princes and churchmen, including Donnchad Mac Fáeláin with 2,000 followers. Later that year the princes of west Leinster, Fáelán among them, joined Ruaidrí's campaign against the Mac Lochlainn in Tyrone, but the new balance suffered a setback in August, when Mac Murchada returned with English troops and reconquered Uí Chennselaig. Ruaidrí and Diarmait Ua Máelshechlainn of Meath, probably with Fáelán's aid, forced Mac Murchada's submission, but in May 1169 more English troops landed, allowing Mac Murchada to take Ostman Wexford and devastate Ossory. Thereafter Mac Murchada and his son Domnall Cáemánach (qv) (d. 1175) turned north, entered Kildare, and in a savage campaign devastated the kingdoms of Uí Muiredaig and Uí Fáeláin, headed respectively by Gilla Chomgaill Ó Tuathail and Fáelán (whom the Song of Dermot in recounting this event labels a traitor). Dublin quickly submitted to him at this time. Mac Murchada then attacked Domnall Mac Gilla Pátraic of North Ossory again, provoking Ruaidrí to action. After a struggle amid the forests of Uí Chennselaig, Ruaidrí and Mac Murchada came to terms: Ruaidrí confirmed the Leinster kingship to Mac Murchada, who in return recognised Ruaidrí as high-king; Mac Murchada was to send the English home, while Ruaidrí took as hostage Mac Murchada's last legitimate son, Conchobar, to whom he promised the marriage of his daughter.
But Mac Murchada broke his word and on 23 August 1170, with his son-in-law Richard fitz Gilbert de Clare (qv) (d. 1176), better known as Strongbow, launched a new campaign in Leinster. After outmanoeuvring Ruaidrí's army at Clondalkin, he took Dublin on 21 September, expelling its king to the Western Isles. With Ruaidrí in disorder, Mac Murchada and Strongbow struck at the lieutenants of the Uí Chonchobair throughout Leinster, forcing Fáelán and Domnall Mac Gilla Pátraic to flee their kingdoms. Mac Murchada was now a serious contender for the high-kingship, but he died suddenly in May 1171, and Strongbow became his successor. During the summer the Ostman king of Dublin returned from the Western Isles, bringing a fleet with him, but he was routed and executed. Later in the summer Fáelán with Archbishop Lorcán Ua Tuathail (qv) (Laurence O'Toole) of Dublin and Murchad Mac Murchada roused the Leinster nobility against the successors of Mac Murchada, and Ruaidrí struck simultaneously at Strongbow, joining the Leinster army and a Manx fleet to besiege Dublin. The siege lasted through August and September 1171, reducing the city to desperate straits. With success within his grasp, Ruaidrí dictated terms of a peace, allowing Strongbow to retain the Ostman towns of Dublin, Wexford, and Waterford, but rather than accept his conditions, the English attacked and routed the large Uí Chonchobair force at Castleknock some time in September. The breaking of the blockade of Dublin gave the English the upper hand, and they attacked the Leinstermen. Bereft of Ruaidrí's protection, Fáelán and the other Leinster nobility welcomed the arrival in Ireland of Henry II (qv) in autumn 1171. Because Henry was eager to check Strongbow's ambitions, a throng of Irish princes, including Fáelán, scrambled to Dublin to avail themselves of the king's protection and took part in the feasts that he lavished upon them. However, their political pragmatism did not save them, for Henry confirmed Leinster to Strongbow after his submission and granted its sub-kingdoms to English adventurers.
From 1172 onwards the English consolidated their hold on east Leinster, encouraging the Irish leaders in the more accessible parts of that region to acknowledge their supremacy and thus drawing them steadily into the feudal net. Despite submitting to Henry, concluding a private peace with Strongbow, and performing feudal service, Fáelán had his kingdom of Uí Fáeláin divided into three cantreds, which Henry granted in 1171–2 to Maurice fitz Gerald (qv) (d. 1176), Robert fitz Stephen (qv) (d. 1185), and Meiler fitz Henry (qv) (d. 1220). Later the king reversed his decision, ceding the cantreds to Strongbow, along with the port towns of Wicklow and Wexford, perhaps as a reward for Strongbow's good service in Normandy in 1173. For his part, Strongbow confirmed Henry's grants to fitz Gerald and fitz Henry but overturned fitz Stephen's in favour of his own supporters, the Hereford brothers. This led to a prolonged legal dispute: in 1176, upon the death of Strongbow, fitz Stephen appealed to Henry but despite assurances from the king his cantred remained in the possession of the Herefords.
At first Fáelán grudgingly accepted the incorporation of Uí Fáeláin into the new county of Kildare, and he attended a gathering held by Stronghow at Meath in 1173, but he and other Leinster princes were aggrieved over the loss of their influence and land. In July 1174 Conchobar Máenmaige Ua Conchobair, Ruaidrí's ablest son, with Domnall Mór Ua Briain (qv) (d. 1194), king of Thomond, destroyed a large English force at Thurles, encouraging the high-king to cross the Shannon and march to Dublin. Fáelán, for whom this was the best chance to reverse Strongbow's division of his kingdom, rode to meet Ruaidrí's advancing forces. The Uí Chonchobair and its allies wasted much of Meath, sacking Trim castle, and penetrated to the outskirts of Dublin, but it failed to deliver a telling blow to the English. The withdrawal of the royal army exposed the high-king's clients in Leinster to the inevitable English backlash, which culminated in the complete ransacking of Uí Fáeláin, Uí Cairpre, and Meath.
After 1174 Fáelán's resistant attitude to the English changed. The devastation of Uí Fáeláin demonstrated that the high-king could not protect him effectively, and any lingering hopes of his protection were dispelled on 6 October 1175, when, by the terms of the treaty of Windsor, Ruaidrí acknowledged the overlordship of Henry II, effectively ceding his control of much of west Leinster and abandoning his clients. Fáelán now became a faithful vassal of Strongbow. In 1177 Maelmorda Mac Fáeláin, perhaps Faelan's son, was killed by the Uí Thuathail of Uí Muiredaig. His death coincided with the arrival of a second wave of settlers into Leinster from the Clare lands in Wales and England, and the enforcement of Strongbow's earlier grant of Uí Muiredaig to Walter de Riddlesford. This suggests that the Meic Fáeláin were either forced southward into Uí Muiredaig by colonist pressure, or that they were now auxiliaries in the service of the English. Between 1189 and 1203 Fáelán was granted lands at Killarney (identified as being within the territory of Cairbre (Carbury), an area greater than the modern barony of Carbury, Co. Kildare). Before 1203 Fáelán in turn granted Killarney to the priory of Clonard. Thus Fáelán appears to have been compensated for losses in Uí Fáeláin with lands in Meath and Offaly, and seems to have acted as a guardian of the marches against the Uí Chonchobair Failge of Offaly, Uí Chairpre of Carbury, and Uí Máel Sechlainn of Meath. Grants preserved in the register of St Thomas's, Dublin, also reveal that the Meic Fáeláin enjoyed good relations with the Herefords, who held the Uí Fáeláin cantred of Cloncurry; it has been suggested that the motte and manor near Cloncurry church was a later Mac Fáeláin residence.
The last great king of Uí Fáeláin, Fáelán Mac Fáeláin, died a monk at Meiler fitz Henry's newly founded abbey of Greatconnell (Kildare) in 1203. His dynasty was the greatest Irish loser during the English conquest of Leinster; the Meic Fáeláin never recovered their former power, but became in the later thirteenth century a largely ecclesiastical family.