n says seven but his plan shows eight) running north and south.
The east and west streets, with two exceptions, lay some 320 ft. from
one another. The north and south streets varied, some observing that
distance, others being no more than 260 ft. apart. As a result, the
rectangular house-blocks varied also in size. The largest seem to be
those which fronted a street that crossed the town from east to west,
from the Imperial Palace to the Baths and the West Gate, and
corresponds roughly with the present Kaiserstrasse. This may well have
been the _decumanus_, the main east and west street of the 'colonia',
and hence the house-blocks fronting it may have been unusually large
(p. 77). One of them, near the Neumarkt, reached the awkward size of
nearly 3-1/2 acres (320 x 460 ft.). Others elsewhere were smaller,
many measuring 320 x 320 ft., and others again 320 x 245 ft., rather
less than 2 acres. In general, the 'insulae' on the east and west
sides of the town were larger than those in the centre. The whole has
a resemblance to Autun, and is more irregular than writers on Trier
are ready to allow.[107]

[107] Graeven estimated that, except in the central street, all
the 'insulae' measured 300 Roman ft. (290 English ft., 88
metres), but his plan suggests rather 100 metres. We need in
reality that larger plan which he did not live to complete.

How many houses may have occupied either a large or a small 'insula'
is uncertain; indeed, we know next to nothing of the private houses of
Roman Trier. Nor can we fix the number of the 'insulae'. On the west,
and still more on the east and south-east of the town, much of the
area was not touched by the drainage works and therefore went
unexplored. We have proof only of streets and buildings for a mile in
length and half a mile in breadth.

[Illustration: FIG. 30. TRIER.
From plan by the late Dr. Graeven.]

Nevertheless we may make some guess at the original area. The
streetage itself plainly dates from the original foundation of the
Romano-Gaulish town by Augustus. There is, indeed, no other epoch in
its history, so far as we know it, when a complete laying out could
have been carried through. On the other hand, it is not probable that
the first town was a mile long and half a mile wide. Possibly, as an
acute German archaeologist has suggested, the small 'insulae' in the
south of the town may indicate the line of an original wall and ditch
which, like the first wal