Centuria

Centuria (Latin plural centuriae) is a Latin substantive from the stem centum (a hundred), denoting units consisting of (originally only approximately) 100 men. It also denotes a Roman unit of land area: 1 centuria = 100 heredia. It is sometimes anglicized as century.

Political
In the political context the centuria was the constituent voting unit in the centuriate comices (Latin comitia centuriata), an old form of popular assembly in the Roman Republic, the members of which cast one collective vote.

Its origin seems to be the homonymous military unit, as citizens could serve in both until Gaius Marius' reform shifted the main form of military recruitment from conscription to professional contracts.

Military
The centuria was the pivotal tactical Roman legion unit after the Marian reforms of 107 BC. It originally consisted of a hundred soldiers; later 60 to (ideally) 80 men distributed among 10 contubernia (of 8 men each). The remaining number of men required for a full count of one hundred was taken up by various noncombatants attached for administrative, logistical or other purposes within the legion. Each contubernium (the minimal unit in the Roman legion) lived in the same tent while on campaign or the same bunk room in barracks. Centuriae were grouped by pairs forming maniples, and later into 6-century cohorts.

The whole century was commanded by a Centurion, who was assisted by an Optio or lieutenant and a sergeant Tesserarius. It had a banner or signum which was carried by a Signifer. Also, each century provided a Buccinator, who played a buccina, a kind of horn used to transmit acoustic orders.

On the battlefield, the Centurion stood at the far right of the first row of men next to the Signifer, while the Optio stood at the rear, to avoid, if necessary, the disbanding of the troops and ensure the relay between typical closed order lines used by the Roman army.

However, the first cohort (consisting of the bravest men from the legion) was twice the size of the other cohorts. Each of its five centuriae was a double centuria of 160 men (rather than 80). The first cohort thus consisted of 800 men. Centurions of these first-cohort double centuriae were called primi ordinis, ("first rank"), except for the leader of the first centuria of the first cohort, who was referred to as primus pilus (first file).

Other uses
The term "centuria" was later used during the Spanish Civil War to describe the informal bands of local militiamen and international volunteers that sprang up in Catalonia and Aragon in October/November 1936.