In August of 1170, Milo joined his uncles in sailing to Ireland with Strongbow. Less than a month later, he led one of two bands in an assault on Dublin, his cousin,
Raymond FitzGerald having led the other. These bands sacked the city and slaughtered many of its inhabitants. Milo was afterwards made constable of the settlement. In 1171, the king of Dublin,
Ascall mac Ragnaill, who had successfully fled, returned with 60 ships and assaulted the city. Milo boldly sallied out to meet them, but was quickly driven back. His brother, Richard, however, had remained hidden behind the attackers and fell upon them from the rear, causing a panic which allowed most of them to be killed, while some fled. Ascall was captured and beheaded on Milo's order, having threatened to return if he were ransomed. Shortly thereafter, Dublin was again besieged, this time by
Ruaidrí Ua Conchobair, who brought 30,000 men to this end. Milo led one of three small contingents in a sally outside the castle walls, defeating the besiegers against all odds. Another siege was laid in 1172, led by
Tigernán Ua Ruairc, which Milo ably defeated, once again sallying out to surprise and rout the attackers. Later that year, Milo took part in the capture of
Limerick and was given command of its garrison. Thereafter, he spent two years fighting in England and France, under the banner of
Henry II, together with Robert FitzStephen. In 1177, the two of them were granted, the
Kingdom of Cork, to be held by the
feudal tenure of 60
knights' fees. ==Marriage and children==