During the reign of
Constantine coins in the three
metals suffered a series of changes in the three metals.
GOLD:
To replace the
Aureus (60 per Lb) he introduced the
Solidus (72
per Lb) The
Solidus had as a fraction the
Semis = ½
Solidus
(a. 2.27 grams) and the 1 ½
Scrupulum of around 1.70 grams.
The
Aureus continued to be minted in the Eastern part of the Empire until
the defeat of
Licinius after which the
Solidus
became the sole gold unit of the Empire.
When
Constantine was still Caesar he reduced the
weight of the
Follis in the mints under his control (London, Lugdunum,
Trier). He made a second reduction in March 307 when he was proclaimed Augustus.
Soon after
Constantine made a third reduction leaving
the
Follis in approximately 68 grains.
The reductions of the Follis mentioned above where made to keep in pace
with was being done in the rest of the Empire, but it was in 312 when Constantine
really begun applying modifications on his own initiative.
SILVER:
The Siliqua was a silver coin introduced by Constantine
which had an equivalent of 24 units per Solidus. Although with a new name
seems to have been equal to the Argenteus of Diocletian,
that is 96 per pound. He also introduced the Miliarensis, a silver piece
coined at the rate of 72 per pound. A Siliqua was ¾ of a Miliarense and
this last coin was equivalent to 1/8 of a Solidus.
1 Solidus = 2 Semises =
18 Miliarenses = 24 Siliquae
COPPER:
After the defeat of Maximianus
in the year 312, Constantine and
Licinius replaced the Follis
for a 18 to 20 mm diameter and 48 grains copper coin known to
numismatists as AE 3. This coin survived until the introduction
of the "Gloria Exercitum" type in 330 but was soon after
reduced to 17 mm diameter and 30 grains. The copper coins during
the last 7 years of Constantine life
are frequently found with less that 17 mm in diameter.