GLASGOW ARCHAEOLOGICAL SOCIETY.
which for many reasons demand special treatment, and (iv.) the isolated
finds of one or two or a few coins detected sporadically over the country.
It may be convenient to prefix to these lists some remarks on their
probable significance. First, as to their terminus a quo, the earliest date
which they suggest for the Roman occupation of Scotland. It will be
observed that the earliest coins which are common are the issues of the
Flavian Emperors, Vespasian and Domitian (69-95 a.d.), while coins of
Trajan and Hadrian (96-138 a.d.) are abundant. This fact might suggest
that the occupation began with the Caledonian campaigns of Agricola in the
reign of Domitian. But appearances are here deceptive. In the first place,
the majority of the coins concerned are silver, and the silver coins of
Vespasian and his successors are well known to have remained in full
circulation until the opening of the third century. They occur, for instance,
in hoards deposited in the reign of Severus, such as some noted in List iii.
I may perhaps briefly digress to state the reason for this. During the reigns
of the first four emperors the denarius had maintained a high standard of
weight and purity. Nero, late in his reign, appears to have depreciated it in
both respects, and his successors followed suit, retaining his weight but
somewhat diminishing the purity. As the debasement proceeded, the
economic law asserted itself, and good money was driven out by bad ; the
older and better coins were melted clown, and Trajan actually " converted " a
large part of the pre-Neronian issues, calling them in and re-issuing them
with the alloy and weight of his own issues. The only survivals of the
earlier age were the legionary denarii of Antony and certain other Republican
issues, which owed their preservation to special causes (see " Archfeologia," liv.
490). But the post-Neronian issues, being all at least of much the same
weight, circulated indiscriminately, and coins of Domitian may therefore
indicate occupation of any date from Domitian's reign till that of Severus.
In the second place, the bronze issues, which were not for the most part so
long-lived as the silver of this period, are not, as the lists show, mostly
Flavian, but belong to the second century, and largely to the reign of Pius
himself, the builder of the vallum. I am inclined, therefore, to think that
the evidence of the coins does not really support the theory that Agricola
commenced a permanent occupation of southern Scotland. It is very
probable that some of the Flavian coins, especially those in List iv., may have
got to their places directly or indirectly through his campaigns. But the
coins do not prove that the forts mentioned in Lists i. and ii., or any similar
sites elsewhere, were occupied by him and were held continuously after him.
Tacitus, be it observed, is equally silent on the subject of any permanent
conquests made by his father-in-law. On the other hand, the coins agree
with the theory that the permanent occupation of south Scotland by the
Romans began when Pius built the vallum about a.d. 142.
Secondly, as to the terminus ad quem, the end of the Roman occupation.
Here the coins speak with unmistakable meaning. Almost everywhere the
latest coins are those of Pius or his immediate successors. Except for one