The numbering of the legions is confusing, due to duplicated and inconsistent numeration by various emperors. Several legions shared the same serial number with others. Augustus numbered the legions he founded himself from I, but at the same retained the serial numbers of those legions he inherited from his predecessors. This policy was generally followed by those of his successors who also founded new legions (there were thus many legions numbered I). However, even this practice was not consistently followed. For example, Vespasian formed two new legions out of units disbanded in disgrace after the Civil War of 68–9, but gave them the same serial numbers (but different titles) as the disbanded ones. Trajan numbered the first legion he founded XXX because there were 29 other legions in existence at that time; but the second Trajanic legion was given the serial number II. XVII, XVIII and XIX, the numbers of the legions annihilated in the Teutoburg Forest, were never used again. (No titles are recorded in surviving ancient sources for these three legions, suggesting that their titles may have been deliberately suppressed due to their disgrace). As a result of this somewhat chaotic numeration, it became necessary to accord a title, as well as a serial number, to each legion in order to distinguish between legions with the same number. The geographical titles indicate (a) the country where a legion was originally recruited e.g. "Italica" = from Italy or (b) peoples the legion vanquished e.g."Parthica" = victorious over the Parthians. Legions bearing the personal name of an emperor, or of his "gens" (clan) (e.g. "Augusta", "Flavia") were either founded by that Emperor or accorded the name as a mark of special favour.