The Roman
pharos
or lighthouse was probably built in the first century
A.D. A similar lighthouse was built on the
Western
Heights and at night guided Roman ships into the
port of
Dubris.
The tower was octagonal outside and rectangular inside
rising to a height of perhaps 80 feet (24m). It had
eight storeys each set back 1 foot (0.3m) from the one
below, which gave the whole structure the appearance
of an extended telescope.
Only the first four Roman storeys remain, the present
topmost storey being a fifteenth century reconstruction.
The present splayed shape of the
pharos is a
result of the severe weathering it suffers in exposed
position and mediaeval refacing.
In the late
Saxon period when the church of St Mary-in-Castro was
built the already ancient
pharos became a
free standing bell tower. The church was built in the
late tenth or early eleventh century and reused much
Roman brick in its construction. Cruciform in plan with
a central tower and aisleless nave, it was considerably
altered in the thirteenth century by Henry III. After
the mediaeval period the church fell into ruin and was
restored first in 1862 and then again in 1883 when the
mosaics on the wall of the nave were added.