It created the principate Roman imperial system. His father's death not only devastated Tiberius but also challenged the future of the principate. Emperor Augustus established the formal position of monarch on the basis of "principate", not "dominion". These commanders were the closest in function to the Imperial Legates of the Principate. Still, beards remained rare among the Romans throughout the Late Republic and the early Principate. Independent slinger units are not attested in the epigraphic record of the Principate. This was particularly the case for Augustus, the first Emperor, who established the Principate. As in the "Histories", Tacitus maintains his thesis of the necessity of the principate. This shows the "castra" (base) where the legion spent the longest period during the Principate. Infantry units mostly fought in close order as did their forebears from the Principate. It was one of the last lineages of the Principate founded by Augustus. By its very nature the "Res Gestae" is propaganda for the principate that Augustus instituted. This defeat was one of the worst Rome suffered during the entire Principate. Infantry adopted the more protective equipment of the Principate cavalry. They continued to supply the senior officers of the army throughout the "principate".