Diligenceandaccuracyaretheonlymeritswhichanhistoricalwritermayascribetohimself；ifanymerit，indeed，canbeassumedfromtheperformanceofanindispensableduty。I
maythereforebeallowedtosay，thatIhavecarefullyexaminedalltheoriginalmaterialsthatcouldillustratethesubjectwhichIhadundertakentotreat。ShouldIevercompletetheextensivedesignwhichhasbeensketchedoutinthePreface，I
mightperhapsconcludeitwithacriticalaccountoftheauthorsconsultedduringtheprogressofthewholework；andhoweversuchanattemptmightincurthecensureofostentation，Iampersuadedthatitwouldbesusceptibleofentertainment，aswellasinformation。
AtpresentIshallcontentmyselfwithasingleobservation。
Thebiographers，who，underthereignsofDiocletianandConstantine，composed，orrathercompiled，thelivesoftheEmperors，fromHadriantothesonsofCarus，areusuallymentionedunderthenamesofAeliusSpartianus，JuliusCapitolinus，AeliusLampridius，VulcatiusGallicanus，TrebelliusPollioandFlaviusVopiscus。ButthereissomuchperplexityinthetitlesoftheMSS。，andsomanydisputeshavearisenamongthecriticsseeFabricius，Biblioth。Latin。l。iii。c。6