6) had established a
five years' interval between home and foreign command that the theory of
the _prorogatio imperii_ vanished and the proconsulate became a separate
office.

Since the theory of the persistence of the republican constitution was
of the essence of the Principate, the consuls necessarily lost little of
their outward position and dignity under the rule of the Caesars. The
consulship was the only office in which a citizen, other than a member
of the imperial house, might have the princeps as a colleague, and in
the interval between the death or deposition of one princeps and the
appointment of another the consuls resumed their normal position as the
heads of the state (cf. Herodian ii. 12). As the presidents of the
senate, who after A.D. 14 elected them to their office, they were the
chief personal representatives of those elements of sovereignty that
were supposed to attach to that body, and they directed that high
criminal jurisdiction which the senate of this period assumed (see
Senate). A restored power of jurisdiction is indeed one of the features
of their position during this time, and it is probable that the civil
appeals which came to the senate were delegated to the consuls. They
also acted for a time as delegates to the princeps in matters of
Chancery jurisdiction such as trusts and guardianship (Mommsen,
_Staatsrecht_, ii. p. 103). The consulship was also a preparation for
certain high commands, such as the government of certain public and
imperial provinces (see Province) and the praefecture of the city. It
was probably due to the fact that the consulship was such a prize, and
perhaps also to the expense imposed on the office by its association
with the celebration of games (Dio Cassius lvi. 46, lix. 20) that the
tenure was progressively shortened. In the early principate the consuls
hold office for six months, later for four to two months (Mommsen,
_Staatsrecht_, ii. pp. 84-87). The consuls appointed for the 1st of
January were called _ordinarii_, the others _suffecti_; and the whole
year was dated by the names of the former.

This distinction continued in the Empire that was founded by Diocletian
and Constantine. The _ordinarii_ were nominated by the emperor, the
_suffecti_ were nominated by the senate, and their appointment was
ratified by the emperor. The consulship was still the greatest dignity
which the Empire had to bestow; and the pomp and ceremony of the office
increased in proporti