Constantine the Great (272-337AD), also known as Constantine I or Saint Constantine, was Roman Emperor from 306 to 337. Though these coins are not struck in his name (they portray the personification of the city of Constantinople), they were issued under his authority.
This follis (also called a nummus - we don't know what the Romans really called them) is made of non-precious metal and weighs about 2.6 grams. The exquisite example in our picture comes from Roma Numismatics and sold for 120 British pounds (about $200 US dollars) in a 2013 auction. It's virtually uncirculated, having just the slightest hint of wear on the rear leg of Victory. You don't see such a specimen every day.
Typical catalog values run like this:
worn: $20 US dollars approximate catalog value
average circulated: $50
well preserved: $180
coins without a legible mint mark are extremely common - divide the above values by 4
There are several issues of these coins which are very common and catalog at lower values.
Coins with the following letters in the exergue (the letters below the horizontal line on the side with Victory) catalog at $10 worn, $100 well preserved:
TR dot P
TR dot S
TRP and TRS with a wreath or palm branch in the left field
SMALA, SMALB, SMAL gamma and SMAL delta with or without a dot, with or without S in the left field and R in the right field
dot BSIS dot
As with all ancient coins, value depends strongly on overall appeal and legibility. Please read our Important Terminology page for information about interpreting catalog values.