On 29 May 1205 some of the greatest among the Angevin clergy and nobility gathered at Winchester cathedral to celebrate the feast of Whitsun (Pentecost). This was not only a religious festival but a coronatio, an occasion on which the king was liturgically elevated and his majesty displayed by the public wearing of his crown. The cruciform cathedral space became a realm in microcosm, where social standing depended on one's nearness or distance from the rex coronatus. After the ecclesiastical dignitaries, the spaces closest to the king during the solemn procession into the church, or at the banquet table following the conclusion of the ceremony, were reserved for the first rank of nobility – the earls. This small elite welcomed its newest member on Whitsunday when, in a public ceremony apart from the royal coronatio, King John tied a sword around Hugh de Lacy's waist, symbolising his investiture as earl of Ulster.

With the sole exception of William Marshal (†1219), earl of Pembroke and lord of Leinster, Hugh now notionally outranked every other member of the settler community in Ireland, including his elder brother, Walter. Earls did not wear crowns, but dignitas could still be conveyed in other ways. An unmistakable ostentation is detected in one of Hugh's earliest comital charters, ‘given by our own hand at Rathbeggan (bar. Ratoath, Co. Meath) on the thirteenth of January in the second year of our earldom (1207)’. Those close to the earl could also lay claim to the honour bound up in his comital title. Around 1270, almost three decades after Hugh's death, his second wife was still styling herself ‘Emelina de Lacy, countess of Ulster’ in charters to her chantry chapel in Wiltshire. Emelina had since remarried to a grandson of Henry II, but for her a connection to the comital title superseded even a link to Plantagenet royal blood.

Some great men would never possess an earldom, but those created earls were almost always great men. There is no escaping the fact that, before 1205, Hugh de Lacy was not even chief in the Irish colony for wealth, land and influence. For this reason historians have struggled to unravel the ‘complete mystery’ of Hugh's promotion.