Pap (Պապ; Papes; circa 353 AD – 374) was king of Armenia of the Arshakuni dynasty from 370 to 374. He was the son of King Arshak II and is notorious for poisoning the Catholicos of Armenia Nerses the Great.
During the siege, Arshak's wife Parandzem appealed to Cylaces and Artabanes in the name of her husband who defected back to the Arshakuni monarchy and engineered the escape of Pap. Themistius reported of Pap's arrival at Valens' court in Marcianople where the Emperor was wintering. Valens bade him to stay at Neocaesarea in Pontus Polemoniacus three hundred kilometers from the Armenian border. In 369, Pap returned to Armenian territory at the request of the nobility. He was accompanied by the comes et dux Terentius but was not yet endowed with a royal rank.
Shapur contacted Pap who was still in hiding and tried to persuade him to come over to his side. Under Shapur's influence Pap murderded the duplicitious Cylaces and Artabanes and sent their heads to the shahanshah as a sign of loyalty. In the spring of 370 Shapur preparded a massive invasion of Armenia which was realized in the spring of 371. Valens' generals Traianus and Vadomarius met the Persian force in Armenia at Bagavan and came off victorious. Faustus of Byzantium gives considerable credit for the victory to sparapet Mushegh Mamikonian. During the ensuing battles more Armenian territories were reclaimed from the Persians, including Arzanene and Corduene which were ceded to Persians by Jovian in 363.
By the end of the summer Shapur retreated to his capital at Ctesiphon and Valens went back to Antioch. Shapur was unable to confront the massive Roman buildup in Armenia as a result of his preoccupation with Kushan attacks in the eastern realm of his empire. While peace prevailed with Persia, the situation inside Armenia began to crumble.
Terentius sent two generals with scutarii (shielded cavalry) familiar with the local terrain after Pap, an Armenian named Danielus and an Iberian named Barzimeres who failed to capture and execute Pap. Both generals gave an excuse that Pap had used magical powers to avoid capture and used a dark cloud to mask his party. Faustus' in his Epic Histories also claimed that Pap was possessed by devs (demons). This could have simply been an attack against Pap's sympathies towards Arians and pagans. Valens then assigned Trainaus to gain Pap's confidence and murder him. Trainaus murdered Pap in 374 during a banquet which he had organized for the young king.Ammianus drew parallels between the treacherous murder of the Quadi King Gabinius by Valenitian and the murder of Pap by Valens, who also wrote that the murder of Pap haunted Valens prior to the Battle of Adrianople.
The Armenian nakharars still loyal to Pap did little to protest as a result of a large Roman army present on Armenian territory. The new Roman nominee for a king was accepted virtually by everyone. It was another Arshakuni and Pap's nephew, who grew up in Rome named Varazdat that began to rule under the regency of Mushegh Mamikonian. The Mamikonians were notoriously pro-Roman. Shapur had long been courting Pap and he was infuriated when Pap was murdered and a new Arsacid placed on the Armenian throne instead.