Contubernium, centuria and manipulus

[Nathan Ross]

I have generaly assumed that the contubernales were all from the same centuria, but I never came across a source that states that clearly

The 8-man 'tent group' is found in (Pseudo)-Hyginus's De Munitionibus Castrorum:

Papilio unus occupat pedes X... tegit homines VIII. Plena centuria habet milites LXXX: erunt papiliones X

which means something like: "One tent occupies 10 feet... and holds 8 men. A full century has 80 men, therefore ten tents"

This certainly implies that the 8-man group is part of the 80-man century!

Note that Hyginus does not call the tent group a contubernium here.

I wonder if some ancient source could give me some more informations about the actual composition of a contubernium.

Hyginus probably dates from some time in the 2nd Century AD. Vegetius says that the centuries were divided into contubernia of 10 men each, and each contubernium shared a tent under the charge of a soldier called the decanus, or caput contubernii; he also mentions that these 10-man contubernia were called maniples. He goes on to say that the full century comprised 110 men (10x10, plus 10 decani) under a centurion. (Vegetius, Epitoma, II, 13-14)

Some historians have assumed that Vegetius, writing in the late 4th or even early 5th century, was mistaken in his numbers. But his estimates have some support - the biography of Pescennius Niger in the Historia Augusta (itself probably late 4th century) mentions that ten commanipulones had shared a stolen chicken and had been punished for it - implying that ten (or eleven, including the thief?) comprised a tent party. The 6th-century Strategikon also refers to a contubernium as a dekarchy or group of ten.

An inscription from Perge, dated to c.AD500, gives figures for a military unit that can be reconstructed to suggest centuries of 110 men, divided into subunits of 11 - although this is very hypothetical, it might give some support to Vegetius's claims.