Phriapatius

Phriapatius (Persian: فریاپت‎‎ /ˌfraɪəˈpeɪʃəs/) or Priapatius /ˌpraɪəˈpeɪʃəs/, sometimes called Phriapites /ˌfraɪˈæpᵻtiːz/, was the king of the Parthian Empire from 185 BC to 170 BC. He was the grandson of Tiridates I (246–211 BC), the brother of Arsaces I (250–211 BC), the founder of the Parthian Empire.
He ruled in the period following the invasion of Parthia by the Seleucid King Antiochus III (223–187 BC).
He was the father of three Parthian kings, Phraates I (170–165 BC), who was his successor, Mithridates I (165–132 BC), and Artabanus I (138–124 BC).