The Square Castan is a set of archaeological remains from the antique Gallo-Roman city of Vesontio, which is presently the French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 city of Besançon

Besançon

Besançon , is the capital and principal city of the Franche-Comté region in eastern France. It had a population of about 237,000 inhabitants in the metropolitan area in 2008...

.

Description

The square is a vast unidentified semi-circular set, probably from the 2nd or 3rd century. It's located next to the triumphal arch

Triumphal arch

A triumphal arch is a monumental structure in the shape of an archway with one or more arched passageways, often designed to span a road. In its simplest form a triumphal arch consists of two massive piers connected by an arch, crowned with a flat entablature or attic on which a statue might be...

, "Porte Noire".

The Saint-Jean-Baptiste church stood on the site of the square until the French Revolution

French Revolution

The French Revolution , sometimes distinguished as the 'Great French Revolution' , was a period of radical social and political upheaval in France and Europe. The absolute monarchy that had ruled France for centuries collapsed in three years...

. The church was destroyed between 1794 and 1797.

Archaeologist and librarian Auguste Castan launched excavations in 1870. He discovered 8 Corinthian columns

Corinthian order

The Corinthian order is one of the three principal classical orders of ancient Greek and Roman architecture. The other two are the Doric and Ionic. When classical architecture was revived during the Renaissance, two more orders were added to the canon, the Tuscan order and the Composite order...

, remains of the water distribution pond which collected the water brought by the Roman aqueduct

Roman aqueduct

The Romans constructed numerous aqueducts to serve any large city in their empire, as well as many small towns and industrial sites. The city of Rome had the largest concentration of aqueducts, with water being supplied by eleven aqueducts constructed over a period of about 500 years...

 of Arcier, and the remains of a hemicycle that has an inner diameter of 54 meters.

What was it?

Auguste Castan identified it with the antique theater of Vesontio. The hemicycle may also have constituted a podium which supported the colonnade

Colonnade

In classical architecture, a colonnade denotes a long sequence of columns joined by their entablature, often free-standing, or part of a building....

 of an overcast portico

Portico

A portico is a porch leading to the entrance of a building, or extended as a colonnade, with a roof structure over a walkway, supported by columns or enclosed by walls...

: it delimits a raised esplanade

Esplanade

An esplanade is a long, open, level area, usually next to a river or large body of water, where people may walk. The original meaning of esplanade was a large, open, level area outside fortress or city walls to provide clear fields of fire for the fortress' guns...

whose exact function is unknown at the present time.

An English garden

An English archaeological garden was created in 1870 to brighten up the remains. It was opened to the public in 1874 and took the name of Auguste Castan in 1898.