In the second half of the 4th century BC the city of Taras (Roman Tarentum, today's Taranto), threatened by the indigenous peoples around her, called on Sparta, her mother city, for military support. In the following decades, several military leaders came to south Italy to assist in the defense of Taras; other South Italian cities became involved in the war as well.
During that time, certain features of the silver coinage reflect the organization required by increased military activity. Some signatures on Tarantine coins recur on coins of Metapontum, Thurii and Heraclea. These are possibly the names of officials whose function may have been to coordinate financial efforts at a federal level. Another feature pointing in the same direction is the issue by Taras of numerous varieties of diobols with the head of Athena on the obverse and Heracles fighting a lion on the reverse. They are very close in appearance to diobols struck at Heraclea, yet bear the legend TAPAR.