Note 2 — Chapter XXXIV
Reading edition
Although the backbone of the Danish power was broken at Clontarf, desultory warfare with them did not cease for long after. Even so late as 1021 they were able to penetrate into the city of Armagh for the seventeenth time during two hundred years, and burnt the whole city to the ground, with its churches and books. Within two years of the battle of Clontarf they burned Glendalough and Clonard.