In 276, the Goths attacked the Roman Empire. The Gothic-Therving King, mocking the Roman Emperor Marcus Aurelius Probus Augustus, challenged him to a battle.
Twenty-five years earlier, in June 251, the Gothic King Cniva killed Roman Emperor Decius and his son Herennius Etruscus in the Battle of Abritus. This was the first time for a Roman Emperor to be killed in battle.
Well-aware of this, Emperor Probus did not risk accepting the battle. He summoned his best military commander Licinius who told the emperor that only Armenian Prince Trdat (future king of Armenia Trdat III), the son of Armenian King Khosrov, was capable of fighting against the Gothic king.
Prince Trdat put on the clothes of the Roman Emperor and stood before the Gothic king. Trdat clashed with his opponent on horseback and defeated him.
The Gothic king surrendered to Trdat. He was captured and escorted by the prince to the court of Emperor Probus. Two years later, Prince Trdat acceded to the Armenian throne as King Trdat III the Great.
Source: “The Roman Eastern Frontier and the Persian Wars (AD 226-363), A Documentary History”, Volume 1, ed. by Michael H. Dodgeon, Samuel N. C. Lieu, Routledge, 1991.