Know it's not thread for it, but responding to OBrian here;
In Ireland in 1297, the descendants of Brian were increasingly marginalized, due to the Eoghanacht family of the Mac Carthaig reclaiming kingship of Munster. The Ui Briain tribe was relegated largely to Munster and the Aran Islands. Further, the two-handed axemen you refer to were the King's Orphans. They never served kings other than Brian because most, if not all, died at Clontarf, and they were just the orphan sons of Gall Gaedhil, mainly from from Cork and Limerick, who were adopted to serve the king; they weren't really any kind of 'official' unit or served any major capacity in an Irish army except for Brian's personal army.
Cavalry existed in much larger numbers as the 'horse-boys', who skirmished with javelins. They were a regular contingent in Irish armies used to harass. They would be the attendants of higher ranked warriors and professional soldiers who weren't expected to engage in a melee, so probably wouldn't often carry a shield, since they were meant to rush, hurl javelins, and retreat. There were quite large numbers of them. Between them and superior cavalry were regular soldiers on horseback, using a hand lance and javelins as well, but meant more for chasing routers and ambushing. Above them were royal cavalry contingents, which were themselves composed of the sons of high ranking ignoble aristocrats and nobility. Irish horsemen were often depicted hooded, incidentally. Irish horse was primarily all intended for skirmishing, but the professionals were better equipped for a melee, and their actual rough equivalent of knights would have armor. Irish horse rode on ponies instead of destriers due to the terrain in Ireland.
Irish infantry was notably light for the most part, wearing padded coats or the heavier acton, or cuton, a quilted body coat common in most of Europe at the time. The most common weapons were spears. Swords, axes, cudgels, pikes, and long polearms also saw use. Javelins of various sizes were extremely common. Longbows were not imported, the technique of making them was imitated from Welsh mercenaries as early as 1080. Mail was expensive still, and saw use primarily among wealthier soldiers and bodyguards. The Irish dressed still in the old style (a long shirt, called a leine or leint, and a short cloak called a bratt, which could be decorated with plaids, stripes, checks, etc., or left blank, all as symbols of societal standing), with the addition of deeper sleeves on their longshirts. They often had their legs exposed though, and many would be barefoot. Heavier Irish infantry was a combination of mercenary Galloglaich, homegrown imitations, and native bodyguards. As an aside, axes existed in Ireland as a weapon predating viking invasions (some bog bodies show axe wounds, and axe heads are at times found near other weapons that can be dated to earlier periods). Helmets at the time were mostly copies of Norman and imported French and Iberian designs. Simple iron round helmets also saw plenty of use, as did iron 'war hats', in addition to a plethora of leather and padded caps. Shields were a mixture of round shields, heaters, and kites., some mid-sized oval-ish shields as well. The lowest Irish soldiers though would wear practically no armor, carry light shields, and were armed lightly with short spears and long daggers, and a lot of small javelins with flights, called darts, used to disrupt enemy positions.
Also, there was not a single type of Irish, but two, the Anglo-Irish (Norman families who had adopted much of Irish culture), and the old Gaelic Irish. Norman Irish families were usually better connected and often wealthier, though rich native families inhabitted areas around the coastal cities, or the cities themselves (such as Irish merchant princes who dwelled in Galway), and Irish pirating families in the west were usually pretty rich from taxing said merchants for safe passage.
The primary, very rich native Irish royal families were the MacCarthy, led by the MacCarthy Mor, in Munster, of the traditional Eoghanacht tribe, who ruled Cashel, capitol of Munster, the MacMurrough in Leinster (the family who'd invited the Cambro-Norman Invasion to restore their king), the O'Rourke and O'Reillys in the kingdom of Breifne (a buffer between Ulster, Connacht, and Meath), the O'Neills and O'Donnells in Ulster, and the O'Connors of Connacht and part of Meath, the ancient rulers of Connacht. The O'Brien/Brian family still administered Thomond and the Aran Islands, but was in a rivalry for control of Thomond with the Norman de Clare family. The political scene of Ireland is vastly more complicated than famous lords and warriors being descended from one or two people, though mind the Irish were so heavily intermarried politically that most kings were related somehow. However, 'royal lines' didn't exist really in Irish society, though dynasties did. Succession didn't go to the sons of the current king, but to his brothers, uncles, cousins, etc., through an elective position called the Tanist, who would be selected from eligible members of those that possessed rigdamna, a complex system of descent that chose possible successors from an extensive pool of potentials.
The heads of these families, with anglicized surnames for simplicities sake, were:
MacCarthy - Domnall Ruad MacCarthy (by this time quite elderly), king of Desmond and the great bulk of Munster
O'Brien (in Thomond) - Toirrdelbach O'Brien, ruled northern Munster
O'Brian (in Aran) - Possibly a guy named Cobthach O'Brian, but I'm not sure. A pirate lord though, really
MacMurrough - Muiris mac Muirchertach MacMurrough (Or MacMurrough-Kavanagh) - Of Norman and Irish descent, ostensibly king of Leinster
O'Neill - Domnall O'Neill, king of Ulster (actually considered king of Tir Eoghain and Ailech), though he was opposed by Richard Óg de Burgh, Earl of Ulster as recognized by the English
O'Rourke - Amlaib MacArt, king of the O'Rourkes and O'Reillys, ruled Breifne, was from the O'Rourke
O'Connor - Aedh O'Connor, Irish king of Connacht, opposed numerous Norman families with the aide of his vassals and cousins, as well as fought his cousins and other Irish
