The Basilica at Cosa

The basilica of Cosa was built around 150 B.C. and is one of the earliest buildings of that type. We can see very clearly the transition from the Greek open stoa to the closed basilca. Like the example at Ardea it has an open collonade adjacent to the forum.

The building is located at the north-east corner of the forum between a block of earlier so-called public atria and the curia. This location between two earlier buildings explains the rather unusual proportions of this basilica.

B) public atria C) basilica D) curia

The nave has 4 x 6 columns. The lower diameter of the columns being (probably) 2 1/4 feet. The axial intercolumniation of the long side is 16 3/4 feet and the total axial length of the nave is 83 3/4 feet.
It is more difficult to define the position of the columns on the short sides, but from the few remains an interaxial distance of 17 3/4 feet may be assumed with a total axial width of 53 1/4 feet.

This nave was surrounded by aisles 16 3/4 feet wide (planned) on the short north-west and south-east sides, 17 1/4 on the south-west side and 15 on the north-east side, measured from column axes to the wall. Roughly gives this a proportion to the nave of 5/7 of the total length and 3/5 of the width of the basilica. This prefigures one of the rules given by Vitruvius, where he prescribes that the width of the aisle must be 1/3 of the width of the nave.

An interesting feature is the appearance of a 'tribunal' in the north-east wall. The width of this tribunal is 29 feet wich is the sum of the width of the short aisles. In fact the width of the north-west aisle was reduced to 13 3/4 feet (measured from the plinth of the column to the wall), due to the difficulties with the location between existing buildings. On the south-east side this width between column plint (a square with a side of 3 feet) was 15 1/4 feet. This was not yet the Aedes Augusti as described by Vitruvius but its location within the layout of the basilica is a clear foreshadowing of the Aedes Augusti of Vitruvius' basilica at Fanum.


F.E.Brown, Cosa 1. History and Topography, in memoirs of the American Academy in Rome, 20 (1951), pp.7-113
F.E.Brown, Cosa: The making of a Roman Town, Ann Arbor, 1980
F.E.Brown, E.H.Richardson, L.Richardson Jr., Cosa 3. The buildings of the Forum, in memoirs of the American Academy in Rome, 37 (1993)
J.M.David, Le tribunal dans la basilique: Evolution fonctionelle et symbolique de la république à l'empire, in Collection de l'école Française de Rome 66 (1983), pp.219-241
C.V.Walthew, A Metrological Study of the Early Roman Basilicas, Lewiston-Queenston-Lampeter, 2002
Soprintendenza Archeologica per la Toscana, L'antica città Romana di Cosa

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