Phraates I was a king of the Parthian Empire, ruling from around 176 to 171 BCE. He was the son of Mithridates I and succeeded his father to the throne. His reign is noted for efforts to consolidate Parthian power and expand its territory, particularly in the region of Mesopotamia. During his rule, Phraates I faced challenges from neighboring kingdoms, including the Seleucid Empire. He is remembered for his military campaigns and diplomatic efforts, which helped to strengthen the Parthian state. His reign laid the groundwork for future Parthian kings to further develop the empire.