The Senate was convoked and asked to elect an Emperor, and Tacitus the Princeps Senatus on rising to give his opinion was suddenly acclaimed Emperor by the whole Senate, with the acclamation ‘Tacitus Augustus, the Gods preserve you. You are our choice, we make you Princeps, to you we commit the care of the republic and the world. Take up the Empire by the Senate’s authority. The honour which you deserve is in keeping with your life, your rank, your character’ etc., and the acclamations conclude with the repetition of the formal words, ‘Tacitus Augustus, the Gods preserve you.’ He was thereupon elected, and the Senate proceeded to the Campus Martius, where its choice is announced to the people in these words, ‘You have here, Sanctissimi Milites et Sacratissimi Quirites, the prince whom the Senate has elected in pursuance of the vote of all the armies, I mean the most august Tacitus; so that he who has hitherto helped the republic by his votes, will now help it by his commands and decrees.’ The people greet the announcement with the acclamation: ‘Most fortunate Augustus Tacitus, the Gods preserve you,’ and the rest that it is customary to say. Lastly the Senate’s choice is proclaimed to the army, and the customary Donative is given. Pertinax was suddenly and irregularly acclaimed by army and populace without waiting for the Senate to make an election. Thereupon he proceeded to the Senate, and after delivering an address to the senators he was acclaimed by all, and received from them all honour and reverence, and ‘was sent to the temple of Jupiter and the other sanctuaries, and having celebrated the sacrifice for the Empire, he returned to the palace[8].’ Thus we see that in theory the new Emperor was first elected by the Senate, and then accepted or recognised in the Campus Martius by the people and army with acclamations which followed a definite and fixed ritual, and finally the Donative originated by the Emperor Claudius, and followed by his successors, was bestowed. But in actual fact the election by the Senate tended to become more and more a very perfunctory affair, and the choice of an Emperor came more and more to fall into the hands of the armies. The Emperor had, however, some power in providing his successor. He could and often did nominate a colleague who would normally possess a right of succession. But while he was merely colleague in the Empire, though he was invested with some of the marks and functions of the Imperial dignity, he had no actual ‘imperium.’ There were also certain definite imperial insignia, such as the purple cloak, once the mark of a general in the field; the laurel wreath, which the Emperor habitually wore; the purple-striped toga and tunic; and the scarlet senatorial shoes.