The Triangular Forum takes its name from the unusual shape of the site. It was probably laid out during the Samnite period in the second century B.C. It was entered by way of an elegant portico of tufa Ionic columns on its shortest side. It had a portico with ninety-five Doric columns around three sides leaving only the south-west side open to allow views of the coast.
Inside the entrance was a fountain and a statue to M. Claudius Marcellus, nephew of the Emperor Augustus (the base now only remains). The southern part of the Forum contained a Doric Temple built in the 6th century B.C. (For details see elsewhere).
