[6] In the late 9th century, bishop Theodosius, who had acted as papal legate to the court of Constantinople, build a chapel for the relics of Barsanuphius of Gaza, a hermit and desert father.

The Chronicum Northmannicum states that a battle took place at Oria, and that Humphredus (Onophrius), the brother of Count William Iron-Arm, conquered the Greeks; he died the next year.

His brother Count Robert Guiscard captured Hydruntum and Castra Minervae, and in 1056 he seized Taranto, but was repulsed; he took it permanently in May 1060.

This brought a sharp rebuke from Urban II ten years later[14] in the form of a letter to Bishop Godinus, warning him that he should keep to his episcopal seat in Brindisi and not engage in consecrating chrism, ordaining priests, and holding synods at Oria.

[18] Frederick II (1194–1250) built a castle on the hill of Oria, perhaps beginning in 1233, when he also fortified Naples, Trani, Bari, Brindisi, Albanese, Pagano and Papatodero.

He also gave the Archbishop of Brindisi the piece of property on the eastern side of the hilltop where the castle was being built as the site for a new church, which was much later to become Oria Cathedral.

[19] In 1219, as he was returning from his unsuccessful trip to Syria to convert the Sultan of Egypt, Saint Francis of Assisi visited Oria and began the establishment of a Franciscan convent there.

[22] The town was erected into an episcopal see on 8 May 1591 by Pope Gregory XIV,[23] after the death of the Spaniard Bernardino de Figueroa of the Roman Catholic Archdiocese of Brindisi-Ostuni in November 1586, and an interregnum of four and a half years.

[26] On 23 January 2010, Pope Benedict XVI named Father Vincenzo Pisanello a priest of the archdiocese of Otranto and Episcopal Vicar for Administration and Pastor of the Parish of Saints Peter and Paul Church in Galatina, Italy (Lecce), as Bishop of Oria.