Legionary rankers were relatively well-paid, compared to contemporary common labourers. Compared with their subsistence-level peasant families, they enjoyed considerable disposable income, enhanced by periodic cash bonuses on special occasions such as the accession of a new emperor. In addition, on completion of their term of service, they were given a generous discharge bonus equivalent to 13 years' salary. Auxiliaries were paid much less in the early 1st century, but by 100 AD, the differential had virtually disappeared. Similarly, in the earlier period, auxiliaries appear not to have received cash and discharge bonuses, but probably did so from Hadrian onwards. Junior officers ("principales"), the equivalent of non-commissioned officers in modern armies, could expect to earn up to twice basic pay. Legionary centurions, the equivalent of mid-level commissioned officers, were organised in an elaborate hierarchy. Usually risen from the ranks, they commanded the legion's tactical sub-units of "centuriae" (c. 80 men) and cohorts (c. 480 men). They were paid several multiples of basic pay. The most senior centurion, the "primus pilus", was elevated to equestrian rank upon completion of his single-year term of office. The senior officers of the army, the "legati legionis" (legion commanders), "tribuni militum" (legion staff officers) and the "praefecti" (commanders of auxiliary regiments) were all of at least equestrian rank. In the 1st and early 2nd centuries, they were mainly Italian aristocrats performing the military component of their "cursus honorum" (conventional career-path). Later, provincial career officers became predominant. Senior officers were paid enormous salaries, multiples of at least 50 times basic.