new earls, John the Scot of Chester, and John de Lacy of Lincoln,
joined the royal forces. Hubert de Burgh took advantage of the
increasing confusion to escape from Devizes castle to a church in the
town. Dragged back with violence to his prison, he was again, as at
Brentwood, restored to sanctuary through the exertions of the bishop of
the diocese. There he remained, closely watched by his foes, until
October 30, when Siward and Basset drove away the guard, and took him
off with them to the marshal's castle of Chepstow.

The tide of war flowed to the southern march of Wales. Llewelyn and
Richard Marshal devastated Glamorgan, which, as a part of the
Gloucester inheritance, was under the custody of the Bishop of
Winchester. They took nearly all its castles, including that of
Cardiff. Thence they subdued Usk, Abergavenny, and other neighbouring
strongholds, while an independent army, including the marshal's
Pembrokeshire vassals and the men of the princes of South Wales, wasted
months in a vain attack on Carmarthen. The king's vassals were again
summoned to Gloucester, whence Henry led them early in November towards
Chepstow, the centre of the marshal's estates in Gwent. Earl Richard
devastated his lands so effectively that the king could not support his
army on them, and was compelled to move up the Wye valley towards the
castles of Monmouth, Skenfrith, Whitecastle, and Grosmont, the strong
quadrilateral of Upper Gwent which still remained in the hands of the
king's friends. Marching to the most remote of these, Grosmont, on the
upper Monnow, Henry spent several days in the castle, while his army
lay around under canvas. On the night of November 11, the sleeping
soldiers were suddenly set upon by the barons and their Welsh allies;
they fled unarmed to the castle, or scattered in confusion. The
assailants seized their horses, harness, arms and provisions, but
refrained from slaying or capturing them. The royal forces never