developed within the legions from the Marian reforms (104 BC) until the military reforms of Diocletian (c. 290). Senior officers Legatus Augusti pro praetore, Imperial Legate: The commander of two or more legions. The Imperial Legate also served as the governor of the province in which the legions he commanded were stationed. Of Senatorial rank, the Imperial Legate was appointed by the Emperor and usually held command for 3 or 4 years. Legatus legionis, Legion Legate: The overall legion commander. The post was usually filled by a senator, appointed by the emperor, who held command for 3 or 4 years, although he could serve for a much longer period. In a Roman province with only one legion, the legatus was also the provincial governor. In such circumstances, the Legatus was dual-hatted as both Legion Legate and Imperial Legate. The Legion Legate also served as commander of the auxiliary units attached to the legion though they were not formally a part of the legion's command structure. Tribunus laticlavius, Broad Band Tribune: Named for the broad striped tunic worn by men of senatorial rank, this tribune was appointed by the emperor or the Senate. Though generally young, he was more experienced than the tribuni angusticlavii, he served as second in command of the legion, behind the legate. Because of his age and inexperience he was not the actual second in command in battle, but if the legate died he would take command of the legion. Praefectus castrorum, Camp Prefect: The Camp Prefect was third in command of the legion. Generally he was a long serving veteran from a lower social status than the tribunii whom he outranked, and who previously had served as primus pilus and finished his 25 years with the legions. He was used as a senior officer in charge of training a legion, though he could also command a cohort of auxiliaries. Tribuni angusticlavii, Narrow Band Tribunes: Each legion had five lower ranking tribunes, who were normally from the equestrian class and had at least some years of prior military experience. They often served the role of administrative officers. This tribunate was often a first, but optional, step in a young man's political career (see cursus honorum). Centurions The rank of centurion was an officer grade that held much responsibility. The most senior centurion in a legion was known as the primus pilus (first file or spear), who directly