Asses signata (Latin, "stamped bronze", singular aes signatum) consisted of cast lumps of bronze of measured quality and weight, embossed with a government stamp, used as currency in Rome and central Italy before the introduction of the aes grave in the mid 4th century BC. When exactly they were first made is uncertain. Popular tradition ascribes them to Servius Tullius, but due to the high quality of art found on even the earliest specimens, this seems very unlikely. A date in the midst of the 5th century BC is generally agreed on. Designs featured are that of a bull, an eagle, and other religious symbols.