Cerball (d. 909), son of Muirecán and overking of Leinster, the last noteworthy ruler of the Uí Dúnlainge dynasty before the battle of Clontarf, belonged to the lineage of Uí Fháeláin. His father Muirecán, king of Nás and Airther Liphi (Naas and the eastern Liffey plain), was slain (863) by the Norsemen; there is no mention of his mother. Domnall and Máel-mórda, two brothers (or half-brothers) of Cerball, feature prominently in the record. The former, styled rex Laginensium (king of the Leinstermen), fell in an intra-dynastic squabble (884). Cerball's immediate predecessor in the kingship, however, was Muiredach (d. 885) son of Bran (qv) (d. 838), of the rival Uí Dúnchada lineage. Cerball married Gormlaith (qv) daughter of Flann Sinna (qv), the Clann Cholmáin king of Tara; he had at least one son, Cellach.
Certainly, he left a distinct imprint on the historical consciousness of the Laigin. He is commemorated in several poems in the Book of Leinster, including the ‘Song of Cerball's sword’ (LL 44a), where he is credited with an overthrow of the king of Knowth, a claim that must be viewed with caution as this source clearly contains many inaccuracies. Another poem, ‘The quarrel about the loaf’ (LL 46ab), is perhaps more reflective of historical reality; it preserves a pointedly north-Leinster catalogue of Cerball's sub-kings, and apparently celebrates a dispute with the rulers of Osraige concerning the border district of Mag Dála (in south-west Co. Laois).
To all appearances, Cerball had considerable difficulty in establishing control over the province during the 890s. Perhaps he was obliged to make concessions to Uí Dúnchada; it seems that Bran, tánaisi of Leinster (slain 894), was a son of his above-mentioned predecessor Muiredach. Meanwhile, his political independence was compromised as the sons of Cerball (qv) son of Dúngal king of Osraige continued their father's endeavours to dominate Leinster. An entry in the Annals of the Four Masters at 899, although garbled, apparently records the celebration by Diarmait son of Cerball of Óenach Carmain (Fair of Carman, east of Kilcullen, Co. Kildare) – a prerogative of the overking of Leinster – which suggests that the dynasty of Uí Dúnlainge was under great strain. Presumably, such difficulties prompted Cerball son of Muirecán to seek alliance with the powerful Clann Cholmáin and marry Gormlaith daughter of Flann. Despite traditions of other marriages on her part, and claims (reflected in a Book of Leinster text) that her relationship with Cerball was stormy, a poem in the Book of Leinster and also in the ‘Dindshenchas’ (topographical lore) implies that she played a part in the murder of an Uí Muiredaig rival of her husband. It seems, therefore, that Cerball's eventual success in subduing northern Leinster was due, at least in part, to Clann Cholmáin support. When he expelled (902) the Hiberno-Scandinavian rulers of Dublin, he did so in alliance with forces from Brega. Four years later, Cerball accompanied Flann Sinna on a hosting into Munster. Then in 908 he joined in the battle of Belach Mugna (barony of Idrone, Co. Carlow) in support of Flann and Cathal (qv) (d. 925) son of Conchobar against the king of Cashel, Cormac (qv) son of Cuilennán.
Cerball died the following year; the Fragmentary Annals (§424) relate a colourful story of a horse-riding accident at Kildare, while the Annals of Ulster sombrely record that the best of Leinster kings dolore mortuus est (died of an illness). The tradition relayed in AFM of his burial at Cell Chorbbáin (Kilcorban, Co. Offaly) is curious in view of its location. The overkingship of Leinster passed to Augaire son of Ailill of Uí Muiredaig. Cerball's surviving brother, Máel-mórda, king of Airther Liphi, was slain alongside his overlord in 917 at Cenn Fuait (probably Glynn, near the River Barrow, parish of St Mullins, Co. Carlow). His son Cellach, styled rígdamna Laigen (eligible for the kingship of Leinster), was slain in 924. Later kings of the Uí Fháeláin lineage descended from the aforementioned Máel-mórda.