force of his principality,
invaded England with an army of thirty thousand men. He ravaged the
lands of Roger de Mortimer, and of all the barons who adhered to the
crown [w]; he marched into Cheshire, and committed like depredations
on Prince Edward's territories; every place where his disorderly
troops appeared was laid waste with fire and sword; and though
Mortimer, a gallant and expert soldier, made stout resistance, it was
found necessary that the prince himself should head the army against
this invader. Edward repulsed Prince Lewellyn, and obliged him to
take shelter in the mountains of North Wales: but he was prevented
from making farther progress against the enemy, by the disorders which
soon after broke out in England.
[FN [w] Chron. Dunst. vol. i. p. 354.]

The Welsh invasion was the appointed signal for the malecontent barons
to rise in arms, and Leicester, coming over secretly from France,
collected all the forces of his party, and commenced an open
rebellion. He seized the person of the Bishop of Hereford; a prelate
obnoxious to all the inferior clergy, on account of his devoted
attachment to the court of Rome [x]. Simon, Bishop of Norwich, and
John Mansel, because they had published the pope's bull, absolving the
king and kingdom from their oaths to observe the provisions of Oxford,
were made prisoners, and exposed to the rage of the party. The king's
demesnes were ravaged with unbounded fury [y]: and as it was
Leicester's interest to allure to his side, by the hopes of plunder,
all the disorderly ruffians in England, he gave them a general licence
to pillage the barons of the opposite party, and even all neutral
persons. But one of the principal resources of his faction was the
populace of the cities, particularly of London; and as he had, by his
hypocritical pretensions to sanctity, and his zeal against Rome,
engaged the monks and lower ecclesiastics in his party, his dominion
over the inferior ranks of men became uncontrollable. Thomas
Fitz-Richard, Mayor of London, a furious and licentious man, gave the
countenance of authority to these disorders in the capital; and having
declared war against the substantial citizens, he loosened all the
bands of government, by which that turbulent city was commonly but ill
restrained. On the approach of Easter, the zeal of superstition, the
appetite for plunder, or what is often as prevalent with the populace
as either of these motives, the pleasure of commi