Charles Lethbridge Kingsford, 1911 Encyclopædia Britannica, Volume 12… (1911)
“ Owen thereupon took up arms, and when Henry IV. returned from Scotland in September he found north Wales ablaze. A hurried campaign under the king’s personal command was ineffectual. Owen’s estates were declared forfeit and vigorous measures threatened by the English government. Still the revolt gathered strength. In the spring of 1401 Owen was raiding in south Wales, and credited with the intention of invading England. A second campaign by the king in the autumn was defeated, like that of the previous year, through bad weather and the Fabian tactics of the Welsh. ”
