The Roman follis was a large bronze coin introduced in about 294 with the coinage reform of Diocletian. It weighed about 10 grams and was about 4% silver, mostly as a thin layer on the surface. Over a period of time, the follis of Diocletian was revalued and reduced. By the time of Constantine, the follis was smaller and barely contained any silver. A series of Constantinian bronzes was introduced in the mid-4th century.

The word follis means bag (usually made of leather) in Latin, and there is evidence that this term was used in antiquity for a sealed bag containing a specific amount of coins.

Our reproduction and replica Follis coins include Follis of Constantine I (The Great).