Aristobulus I was a ruler of the Hasmonean dynasty in ancient Judea, reigning from 104 to 103 BCE. He was the first Hasmonean to take the title of king, expanding his territory and consolidating power after the death of his father, John Hyrcanus. Aristobulus I was known for his efforts to strengthen the Jewish state and promote Hellenistic culture. During his reign, Aristobulus I also faced challenges from rival factions within Judea and external threats from neighboring regions. His rule marked a significant period in Jewish history, as it represented the transition from a high priestly leadership to a monarchy, influencing the political landscape of the time.