The area was first settled in 500 a.C. as a fortified Messapic city.
In order to improve communication with the Orient, between the years 108 and 110 A.C. , the Emperor Traiano ordered the construction of a Via Publica which was named after him. Monopoli is the city in Puglia that has the longest stretch of the Via Traiana. This is one of the most important Roman roads of the Empire. In 2012 the City of Monopoli created an archeological park around the remains of this ancient road. The difference between this new road and the Appian Way was the shorter distance between Benevento and Brindisi. The Appian Way started in Rome, reaching Benevento and continued on to Taranto, and from here the road continued to Brindisi from which port people could embark toward Greece, the Orient and the Balkans. The Traiana Way which followed an older route, originated in Benevento and crossing the flat tableland up to Canosa continued on to Ruvo where a fork in the road led in two different directions. The internal road went to Modugno, Ceglie del Campo, Capurso, Rutigliano and Conversano, while the coastal road went to Bari, Polignano and Monopoli. These two roads joined again at Egnazia from where the road continued to Brindisi. This road which Emperor Traiano had constructed became the route of choice to reach Brindisi because it was shorter than the Appian Way. It was travelled by military troops, merchants, slaves, pilgrims and, after the fall of Rome, even by hordes of barbarians. There is another important road on the other side of the Adriatic Sea which seems to be the continuation of this road. It is called the Egnazia Way and starts in Dyrrachium (Durazzo), crossing a mountainous area to reach Thessaloniki (Salonica) and continues on to Constantinople (Istanbul).
After the destruction of Gnathia by the Ostrogoth king Totila in 545, its inhabitants fled to Monopoli, from which it derives its name as "only city". In the following centuries the area would be
