Castra

Templeborough Roman fort in South Yorkshire visualised 3D flythrough, produced for Rotherham Museums and Archives

In the Roman Republic and the Roman Empire, the Latin word castrum^[1] (pl.: castra) was a military-related term.

In Latin usage, the singular form castrum meant 'fort', while the plural form castra meant 'camp'.^[2] The singular and plural forms could refer in Latin to either a building or plot of land, used as a fortified military base.^[3]

In English usage, castrum commonly translates to "Roman fort", "Roman camp" and "Roman fortress". However, scholastic convention tends to translate castrum as "fort", "camp", "marching camp" or "fortress".^[3]

Romans used the term castrum for different sizes of camps – including large legionary fortresses, smaller forts for cohorts or for auxiliary forces, temporary encampments, and "marching" forts. The diminutive form castellum was used for fortlets,^[4] typically occupied by a detachment of a cohort or a centuria.

For a list of known castra, see List of castra.

^ A 2nd declension neuter noun. According to Lewis & Short, dictionary item linked in External links, General, either the singular or plural form was used – the plural form, castra, had a possible meaning of "tents".
^ Allen and Greenough. Latin Grammar, Variable nouns, #107. Via Dickinson College Commentaries. Retrieved 14 October 2021.
^ ^a ^b Campbell 2009, p. 4. Included is a discussion about the typologies of Roman fortifications.
^ See Vegetius, Epitoma rei militaris, 3.8. In Clark's translation, section 3.8, we find "Rules for Encamping an Army", last paragraph. "Small fort" is castellum, which Vegetius explains as the diminutive of castra. He conceives of castella as fortified outposts to be manned by cavalry protecting a supply route; i.e., a base from which to conduct patrols.

[1] A 2nd declension neuter noun. According to Lewis & Short, dictionary item linked in External links, General, either the singular or plural form was used – the plural form, castra, had a possible meaning of "tents".

[2] Allen and Greenough. Latin Grammar, Variable nouns, #107. Via Dickinson College Commentaries. Retrieved 14 October 2021.

[CampbellP4-3] Campbell 2009, p. 4. Included is a discussion about the typologies of Roman fortifications.

[4] See Vegetius, Epitoma rei militaris, 3.8. In Clark's translation, section 3.8, we find "Rules for Encamping an Army", last paragraph. "Small fort" is castellum, which Vegetius explains as the diminutive of castra. He conceives of castella as fortified outposts to be manned by cavalry protecting a supply route; i.e., a base from which to conduct patrols.

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