In the first days of May[454] Robert Fitz-Stephen landed at Bannow, between Wexford and Waterford, with thirty picked knights of his own immediate following, and a body of auxiliaries to the number of sixty men-at-arms and three hundred archers.[455] With him came three of his nephews, Meiler Fitz-Henry, Miles Fitz-David[456] and Robert de Barri;[457] and also a ruined knight called Hervey of Mountmorris, uncle of Richard de Clare.[458] Next day an independent adventurer, Maurice de Prendergast, arrived from Milford with ten more knights and a band of archers.[459] Dermot himself came to meet them with some five hundred Irishmen. The united force marched upon Wexford, and took it in two days;[460] they then established their head-quarters at Ferns,[461] and thence made an expedition into Ossory, whose chieftain was specially hostile to Dermot. In spite of overwhelming odds, through all the difficulties of an unknown country full of woods and marshes, and traps laid against them by their skilful foes, the Norman-Welsh knights and archers made their way into the heart of Ossory; and a great battle ended in the rout of the Irish and the bringing of two hundred heads to Dermot’s feet in his camp on the banks of the Barrow.[462] A successful raid upon Offaly was followed by one upon Glendalough, and a third upon Ossory again,[463] till in the following year the state of affairs in Leinster had become threatening enough to drive all the Irish princes and the Ostmen of Dublin into a confederacy under Roderic O’Conor for the expulsion of the intruders.[464] Dermot pledged himself to acknowledge Roderic as monarch of Ireland, and was in his turn acknowledged by Roderic as king of Leinster on condition that he should dismiss his foreign allies.[465] The agreement was however scarcely made when Maurice Fitz-Gerald landed at Wexford with some hundred and forty men;[466] these at once joined Dermot in an expedition against Dublin, and harried the surrounding country till the citizens were reduced to promise obedience.[467] Early in the next year Dermot’s son-in-law Donell O’Brien, king of Limerick or Northern Munster, succeeded by the help of Robert Fitz-Stephen in throwing off the authority of Roderick O’Conor.[468] Encouraged by these successes, Dermot now began to aspire in his turn to the monarchy of all Ireland;[469] but his auxiliaries were numerically insufficient; and the one from whom he had expected most had as yet failed to appear at all.