Lacy, Hugh de (c.1176–1242), earl of Ulster , magnate, second son of Hugh de Lacy (qv) (d. 1186), lord of Meath, and his first wife, Rose de Baderon (‘Rose of Monmouth’), emerged on the Irish scene in 1195 as an ally of John de Courcy (qv), whom he accompanied on de Courcy's expedition to Connacht. In 1201 he governed Meath during the absence of his brother Walter de Lacy (qv), lord of Meath, and accompanied de Courcy to assist Cathal Crobderg Ua Conchobair (qv), king of Connacht, against Cathal Carrach Ua Conchobair (qv); he captured Cathal Carrach and imprisoned him, releasing him only after a fine was paid. De Lacy's relations with de Courcy deteriorated after this. He captured de Courcy (who had refused to submit to King John (qv)) in 1201, but released him when de Courcy's followers promised to cease all raids into the de Lacy lands. In 1203 de Lacy invaded de Courcy's earldom of Ulster and defeated him in a battle near Downpatrick. In August 1204 previous grants of eight cantreds in Ulster and six more in Connacht were confirmed by the king. In September 1204 de Lacy captured de Courcy in battle; in May 1205 he was granted all of de Courcy's lands in Ulster, and was created earl of Ulster.
De Lacy supported his brother against the justiciar, Meiler fitz Henry (qv), in 1206–7, and his earldom was removed by King John in 1210 for his active support of William de Braose (qv). He burned his own castles and retreated to Carrickfergus as John advanced into Ulster; he escaped to Scotland and from there went to France, where he took part (1211–19) in the Albigensian crusade. While his brother made peace with King John, Hugh ignored an offer of pardon if he returned to the service of the English in 1216. In 1220 he joined Llywelyn ap Iorwerth in attacks on the Welsh lands of William Marshal (qv), earl of Pembroke (d. 1231). De Lacy returned to England in 1221 and requested the restoration of his lands; his wife's lands and those he held of his brother were restored (December 1222), but not the earldom of Ulster. He returned to Ireland in the autumn of 1223 and rebelled with the support of the English of Meath; he invaded Ulster, burned Coleraine castle, and besieged Carrickfergus before he was forced to surrender (June 1224) to Marshal, who had been sent to Ireland to deal with the rebellion. His lands were granted to his brother in May 1226, but he was restored to the earldom of Ulster in April 1227 and was summoned to serve the king in France in 1229. He participated in a confrontation in 1234 which led to the death of Richard Marshal (qv), earl of Pembroke, and he was also part of the army that conquered Connacht in 1235; he was granted several cantreds in northern Connacht, but granted them to other English magnates.
De Lacy was summoned to England to give advice to the king in May 1234 and again in April 1237. In 1236 he joined Thomas of Galloway in an attempt to seize the lands of Alan of Galloway, but was forced to come to terms with Alexander II of Scotland. In 1238 some of his men killed an Irish lord, which led to an invasion of Ulster by Domnall MacLoughlin (qv), king of Cenél Eoghan. De Lacy was forced to flee but returned with an army to depose MacLoughlin in favour of Brian O'Neill (qv); the deposing proved to be temporary. He married first Lescaline, daughter of Bertram de Verdun (qv); secondly, Emeline, daughter of Walter de Ridlesford; he had at least two sons, Walter and Roger, both of whom predeceased him. Although he had several daughters his lordship of Ulster was taken into the king's hands after his death (a. February 1242). It was eventually granted to his great-nephew, Walter de Burgh (qv), in 1263.