Who is Aristobulus from The Jewish War and what is their importance?

The first Aristobulus mentioned in the text was the eldest son of John Hyrcanus. When Hyrcanus died after thirty-one years in political power, Aristobulus took over and turned the constitution into a monarchy, after which, he imprisoned his three brothers and mother for contesting his supremacy. Upon his death, his brother Alexander took the throne and ruled for twenty-seven years. He left the throne to Alexandra his wife.