The powers and duties assigned to the emperor were broad and comprehensive. They were, moreover, rapidly enlarged as functions traditionally attached to republican magistracies were transferred one after another to the new executive, and executive action invaded fields which, under the former system, had been consecrated to senatorial or popular control. Finally, by virtue of specific provisions, the substance of which is indicated in the maxim princeps legibus solutus, the emperor was freed from constitutional limitations which might have paralyzed his freedom of action; while his personal protection was assured through the grant of tribunician inviolability (sacrosanctitas) as well as by the sanctions of the Lex Maiestatis. The prerogative was thus built up by a series of concessions, made by the competent authority of senate and people, no single one of which was in theory unrepublican.

— ibid.