['Twas then the time we were in the days]. The poet means:—"Something dreadful has clearly happened; but how can this be, since this is the reign of Cahal-More?" He did not know—in his dream—of Cahal's death.
[Fleckt], spotted.
[Alien sun], a strange sun: it was of course strange, for it glared from the north.
[Shorn beams], not bright, giving a dull gloomy sort of light.
[Skeleton]: the skeleton of a man, a sign of disaster: the skeleton, and the blood spots in the sky, and the "alien sun" were some of the portents.
[Castled Maine]: there are many castles along its banks.
[Teuton], a German.
[Expedition], an undertaking or journey.
[Onslaught], a violent attack.