The exact time of Ioannina's foundation is unknown, but it is commonly identified with an unnamed new, "well-fortified" city, recorded by the historian Procopius as having been built by the Byzantine emperor Justinian I for the inhabitants of ancient Euroia. This view is not supported, however, by any concrete archaeological evidence. Early 21st-century excavations have brought to light fortifications dating to the Hellenistic period, the course of which was largely followed by later reconstruction of the fortress in the Byzantine and Ottoman periods. The identification of the site with one of the ancient cities of Epirus has not yet been possible.