wrote that Nicomedes IV was the son of Nicomedes III by his wife Nysa but according to Granius Licinianus he was a son of Nicomedes III by a first wife called Aristonica, Granius Licinianus claims that Aristonica died after nine days of his birth. He had three half siblings, Nysa by his fathers second marriage to Nysa, and a half brother named Socrates Chrestus from his fathers concubine Hagne and possibly Pylaemenes III by an unknown woman. His reign began at the death of his father. The first few years of his kingship were relatively peaceful, but soon King Mithridates VI of Pontus, one of Rome's greatest enemies during the late Republic, began harassing Bithynia's borders. Nicomedes IV's brother, Socrates Chrestus, assisted by Mithridates VI, defeated Nicomedes IV's army in 90 BC, and Nicomedes IV was forced to flee to Italy. He was restored to his throne by Manius Aquillius due to Rome's influence in the region. However, Aquillius encouraged Nicomedes IV to raid Mithridates VI's territory, prompting Mithridates VI to retaliate again in 88 BC. Nicomedes IV fled once again to Rome. Mithridates invaded and conquered Bithynia and the Roman provinces of Asia starting the First Mithridatic War. The East was seen by the Romans as a province providing an abundance of gold and silver. As such, two powerful Romans, Gaius Marius and the ConsulLucius Cornelius Sulla aimed at a command in the region. After a short civil war, Sulla sailed east and fought Mithridates VI on several occasions over the next three years, and finally in 85 BC, Mithridates VI sued for peace, and was allowed to retain his kingship in Pontus after paying a heavy fine. Nicomedes IV was restored to his throne in Bithynia in 84 BC. The years that followed were relatively peaceful, though Bithynia came more and more under the control of Rome. In 80 BC, young Gaius Julius Caesar was an ambassador to Nicomedes IV's court. Caesar was sent to raise a fleet using Bithynia's resources, but he dallied so long with the King that a rumor of a sexual relationship between the two men surfaced, leading to the disparaging title for Caesar, "the Queen of Bithynia", an allegation which Caesar's political enemies made use of later in his life. During Caesar's Gallic Triumph a popular verse began: "Gallias Caesar subegit, Caesarem Nicomedes,", suggesting that Caesar was the receiving partner in the relationship. It is unknown if a sexual relationship was true or just a story generated by his opponents and Caesar denied its truthfulness vigorously. As one of his last acts as king of Bithynia, in 74 BC, Nicomedes IV bequeathed the entire kingdom of Bithynia to Rome. The Roman Senate quickly voted it as a new province. Rome's old enemy Mithridates VI had other plans for Bithynia, however, and Nicomedes IV's death and bequeathal led directly to the Third Mithridatic War.
