considerably receded. Two gates remain, the principal one being the
east gate, commanded by towers a hundred feet high; while the north is
a postern-gate about five feet wide. The Romans have not left many
traces behind them. Some coins have been found, including a silver one
of Gratian and some of Constantine. Here St. Furseus, an Irish
missionary, is said to have settled with a colony of monks, having
been favourably received by Sigebert, the ruler of the East Angles, in
633 A.D. Burgh Castle is one of the finest specimens of a Roman fort
which our earliest conquerors have left us, and ranks with Reculver,
Richborough, and Pevensey, those strong fortresses which were erected
nearly two thousand years ago to guard the coasts against foreign
foes.

In early days, ere Norman and Saxon became a united people, the castle
was the sign of the supremacy of the conquerors and the subjugation of
the English. It kept watch and ward over tumultuous townsfolk and
prevented any acts of rebellion and hostility to their new masters.
Thus London's Tower arose to keep the turbulent citizens in awe as
well as to protect them from foreign foes. Thus at Norwich the castle
dominated the town, and required for its erection the destruction of
over a hundred houses. At Lincoln the Conqueror destroyed 166 houses
in order to construct a strong _motte_ at the south-west corner of the
old _castrum_ in order to overawe the city. Sometimes castles were
erected to protect the land from foreign foes. The fort at Colchester
was intended to resist the Danes if ever their threatened invasion
came, and Norwich Castle was erected quite as much to drive back the
Scandinavian hosts as to keep in order the citizens. Newcastle and
Carlisle were of strategic importance for driving back the Scots, and
Lancaster Keep, traditionally said to have been reared by Roger de
Poitou, but probably of later date, bore the brunt of many a marauding