The Roman emperor was the ruler and monarchical head of state of the Roman Empire, starting with the granting of the title augustus to Octavian in 27 BC. The title of imperator, originally a military honorific, was usually used alongside caesar, originally a cognomen. When a given Roman is described as becoming emperor in English, it generally reflects his accession as augustus, and later as basileus. Early emperors also used the title princeps alongside other Republican titles, notably consul and pontifex maximus.