A follis is a type of coin that was commonly used in the Roman Empire, particularly during the late Roman and Byzantine periods. Made primarily of bronze, it was introduced in the 3rd century AD as a way to provide a more affordable currency for everyday transactions. The follis often featured the image of the emperor and various symbols, reflecting the political and economic climate of the time. The value of a follis varied, but it was generally considered a low-denomination coin compared to silver and gold coins like the denarius and solidus. Over time, the quality and weight of the follis declined, leading to inflation and changes in the monetary system. Despite this, it remained an important part of commerce in the Roman world.