These facts prove that the first factor in the Irish rally of the thirteenth century was the sense of nationality, intensified by adversity. Of this we shall see new and striking proofs. About this time, the Irish began to strengthen their domestic polity by adopting the custom of tanistry. In 1260, Brian O'Neill led an army of Ulstermen and Connachtmen against the Earl of Ulster's stronghold, Downpatrick. The viceroy, warned of his movements, was there to meet him. Brian was defeated and killed, and, as though his death were a greater glory than his life, he is known to his countrymen of later times as Brian Catha an Dúin, "Brian of the Battle of Down." Three years later, in 1263, when king Hakon of Norway came with his fleet to the Hebrides, he received a message from Ireland. Sir George Dasent, the English editor of the history of king Hakon, undertakes to say quite gratuitously and quite as absurdly that this embassy in 1263 came from the Ostmen of Dublin. The facts are related by Sturla, a contemporary, a councillor of king Hakon, and no doubt on the testimony of eye-witnesses. Sturla and his informants knew the difference between Ostmen and Irishmen. Sturla says that, after Hakon's first arrival in the Hebrides, "there came these messages to him from Ireland, that the Irishmen offered to come into his power, and said they needed much that he should free them from that thraldom which the English had laid on them, for that they held then all the best towns along the sea. But when king Hakon lay at Gigha (off Cantire) he sent men out to Ireland in a light cutter, and that man with them who was called Sigurd the South-Islander (_i.e._ the Hebridean, no doubt as interpreter). They were to find out in what way the Irish invited them to come thither." Before their return, Hakon's expedition had proved unsuccessful. As he lay at Lamlash, in the Firth of Clyde, "thither came to him those men that he had sent to Ireland, and told him that the Irish would keep the whole host that winter, on the understanding that king Hakon would free them from the sway of the English. King Hakon was very much inclined to sail to Ireland, but that was much against the mind of all his people. And so, because the wind was not fair, then the king held a _thing_ (_i.e._ an assembly) with his force, and gave it out that he would give them all leave to sail to the Hebrides as soon as the wind was fair; for the host had fallen short of victuals." It is not unlikely that Hakon gave the Irish to understand that he would come to them later. The entry of his death in the Annals of Ulster shows that at that time, two months after he left Lamlash, he was expected in Ireland. The annalist says: "Ebdonn, king of Norway, dies in the Orkney Islands on his way to Ireland."