By time Aristobulus the older of the warring sons of Yannai inherited the Kingdom of Judea in 67 BCE from his saintly mother Shlomzion HaMalka, nearly 70 years had passed since the death of Shimon, the last of the original five Macabean brothers. (Tragically from the four brothers who we know details of their death, all died violently at the hands of their enemies.)
Since then, the Chashmonaim dynasty had fallen into spiritual decline. Yochanan Kohen Gadol, who served as leader for many years, fell under the spell of the Sadducees in his old age. His war mongering son Yannai, in his lust for land and wealth, led a reluctant and battle weary Jewish nation into wars that were totally unnecessary from a security perspective.
Ultimately Yannai was forced to hire a mercenary army made up of non-Jews, which he turned on his own resentful people. He brought a civil war upon the country in which 50,000 Jews lost their lives. (His brutal execution grounds were recently excavated in the Russian Compound.) To protect his tyrannical rule he fortified a string of desert fortresses, famously among them Masada, which features prominently in future historical episodes.
He left his kingdom in the hands of his wife Shlomtzion HaMalka, the sister of the holy Shimon Ben Shetach. In a dramatic death bed reversal he instructed her to be wary of the Sadducees and to trust only the Prushim (the religious Jews or Chareidim as they would be called today.) The nine glory years of her peaceful and prosperous reign ended with her death in 67 BCE. Unfortunately her two sons Aristobulus and Hyrcanus followed their father’s example of favoring the Saduccees and did not heed his last wishes to side with the Prushim.
Civil war erupted between the two rival brothers and eventually they both appealed for arbitration to Pompei, the famous general of the new world power Rome, who was on his way back to Rome after finally subduing the Persian empire. As often is the case, both sides ended up losers with Pompei taking control of Judea for Rome. He sided with Hyrcanus who became a puppet to his advisor Antipater the Idumean, the man appointed by Rome to hold the real power.
Thus ended nearly 100 years of Jewish independence since the great miracle of Chanuka. The Ramban famously tells us that while the Chashmonaim were great tzadikim, their family line was termintated as a punishment for taking on the Kingdom which belonged to Shevet Yehuda. As Kohanim from Shevet Levi their heritage and birthright the avodah of the Bais HaMikdash. They should not have overstepped their bounds.