Six Imperial Circles were introduced at the Diet of Augsburg in 1500. In 1512, three more circles were added, and the large Saxon Circle was split into two, so that from 1512 until the collapse of the Holy Roman Empire in the Napoleonic era, there were ten Imperial Circles. The Crown of Bohemia, the Swiss Confederacy and Italy remained unencircled, as did various minor territories which held imperial immediacy.