Starting from the 3rd century BC, with the expansion of Rome, rustic villas and masses were built among the cultivated fields, while municipalities were formed along three main roads: from Venosa , through the Murge, to Taranto; from Canosa , through Ruvo , Bitonto , Ceglie , Norba , to Egnazia ; from Ofanto , along the Adriatic coast, to Brindisi and Otranto . At the time of Horace (68-8 BC), Bitetto did not yet exist.
After the fall of the Western Roman Empire and the defeat of the Goths and Lombards , Puglia was reconquered by the Byzantine Empire . During this period, the region bore a heavy tax burden, but was enriched from a cultural point of view: the artistic heritage of the time, in fact, was deeply influenced by the new Byzantine elements.
In those years Bitetto began to unify, forming a single village whose population was growing. It gathered around a monastery established by the Basilian monks in the San Marco district, between Bitetto and Bitritto . Monastery of this type were built at the behest of the Byzantines: in this way, in fact, they were able to exercise greater control over the territory and the population, exploiting the religious and political influence of the monks on the peasant families, enslaved by the gasindi to clear the land.
The land of Bari , under Lombard pressure , became part of Langobardia Minor , then of the Duchy of Benevento . In this period Bitetto was included in the territory of the city of Bari, as evidenced by a very ancient document, dating back to 1021, which is found in the archive of San Nicola di Bari.
During the 11th century Bitetto was elevated to the rank of bishop's seat , as in 1089 the papal bull Quia nostris temporibus of Pope Urban II cited it as a suffragan of Bari. Local notarial registers from the 14th and 15th centuries attest to the existence of a thriving Jewish community devoted to the trade of fabrics and real estate and the rental of animals.
The 15th century saw the progressive worsening of the living conditions of the population of Bitetto: between the end of the 15th and the beginning of the 16th century the city was hit by the plague, killing, according to the records of the time, 3,249 inhabitants. The survivors abandoned their lodgings outside the city walls; the area outside the historic centre would not be repopulated until the early 19th century .