Princeps (plural: principes) is a Latin word meaning "first in time or order; the first, foremost,[1] chief, the most eminent, distinguished, or noble; the first man, first person".[2] As a title, "princeps" originated in the Roman Republic wherein the leading member of the Senate was designated princeps senatus.[3] It is primarily associated with the Roman emperors as an unofficial title first adopted by Augustus in 23 BC. Its use in this context continued until the reign of Diocletian at the end of the third century. He preferred the title of dominus, meaning "lord" or "master".