The system of
denominations from the late
Roman Empire (300 C.E. and after):
For billon/bronze coins (
billon is a very debased metal
alloy containing only a few percent silver or less, the remainder being copper with some lead) the following is generally recognized:
AE 1, sometimes called the Maiorina, sometimes a double-centenionalis. Measures 27-30 mm.
AE 2, sometimes called a
centenionalis. At first it was a coin about 22-26mm and weighing 4.9-6.1 grams, but later--the "
reduced centenionalis" was 20-22mm and about 3.0 to 4.7 grams.
AE 3, early examples are sometimes called a
Nummus, later ones sometimes called a half-centenionalis, they are about 18-22 mm and until about 325 C.E. weighed about 3.0-3.5 grams. From about 326-336 it weighed only 2.5-3.0 grams. After
Constantine divided the Empire between
his sons and half-nephews, 337, the coin was further
reduced to what we call:
AE 3/4, also sometimes called a
nummus These are 15-18 mm and weigh about 1.4-2.0 grams. Starting at this time was an even smaller coin, we call:
AE 4, properly called
nummus minimus, but confusingly also called a
nummus, a small coin, heavily leaded, and devoid of silver. Initially these coins were 13-16 mm and 1.3-1.7 grams but declined in the late 4th and 5th centuries to where they are only 10-12 mm and 0.7-1.0 grams. I have 2 AE 4's of
Aelia Verina (oh, they have her husband,
Leo I on them too) from about the year 470 that are 9.5 mm and 0.7 grams.
