It consisted of roughly 450 legionaries, or thereabouts, depending on the period, and the First Cohort of a Legion was double this in size.
The subsequent sub-divisions were:
- Maniple (a sort of reinforced Company) circa. 120 legionaries.
- Century (Company) circa. 80 legionaries.
- Contubernium (Section) the eight legionaries who shared a tent together.
Should any of this look vaguely familiar, don't forget that, over the course of the last 2000 years, the only organisational models around were largely the Legions and the Roman Catholic Church.