Tiridates I (, Trdat I) was King of Armenia beginning in 53 and the founder of the Arsacid Dynasty, the Armenian line of the Arsacid Dynasty. The dates of his birth and death are unknown. His early reign was marked by a brief interruption towards the end of the year 54 and a much longer one from 58 to 63. In an agreement to resolve the Roman-Parthian conflict in and over Armenia, Tiridates I (one of the brothers of Vologases I of Parthia) was crowned king of Armenia by the Roman emperor Nero in 66; in the future, the king of Armenia was to be a Parthian prince, but his appointment required approval from the Romans. Even though this made Armenia a client kingdom, various contemporary Roman sources thought that Nero had de facto ceded Armenia to the Parthian Empire.