To be honest I have not done an absurd amount of digging on this specific question as of yet, but the scratching around I HAVE done so far seems to be somewhat inconclusive/contradictory, so I just wanted to see if anyone (read: educated professionals) out there might have a definitive source to suggest on the topic or point me in the right direction? I am trying to learn exactly what were the sequence of events that led Judea to becoming a Roman "client kingdom." I am aware of the tetrarchy and the subsequent squabbling over authority after Herod's death in 4 AD, but it is what happened BEFORE that event that I am asking about, if that makes sense. I read that Herod sent a delegation to Rome to ask the Senate if Judea could be accepted into the Empire as a tributary state to gain protection from a northern aggressor, and then I also read that, Pompey simply "conquered Jerusalem" and the rest is history....
Much appreciation if anyone can throw me a bone here! Thanks!
So, this is a bit complicated. Judea was only independent for a short amount of time. But it gained independence from the Seleucids after the Hasmonean revolt and some other political wrangling.
Anyway, in the 1st century BCE Judea was run by a queen, Salome Alexandra (also known by her Hebrew name Shlom-Tzion Alexandra). She took the throne from her second husband, Alexander Yannai (whose brother was Salome's first husband. He came to power after some confusing court intrigue), who died in 76 BCE. Politics at the time were heavily factionalized, between the Sadduccess and Pharisees^1 . Alexander Yannai had been a Sadduccee, whereas his wife and successor favored the Pharisees.
After she died, her two sons fought the same political battle. Hyrcanus II was her designated successor, but his younger brother Aristobulus II was more powerful. The two fought a war of succession, which the younger won after conceding his brother the revenue of the high priest's office (which under the Hasmoneans had generally been held by whoever was king).
However, it didn't end there. Hyrcanus got foreign help from Arabia. After unsuccessfully attacking his brother, he then got help from the Romans, specifically from Pompey. Pompey's invasion was successful, and Hyrcanus was installed as high priest after conquering Jerusalem. But he wasn't independent, and Judea came under Roman authority.
Things get far far more confusing from here. Pompey and Caesar have their war, and Caesar eventually supports Hyrcanus too. However, Hyrcanus is somewhat controlled by his ally, Antipater, who was assassinated. After a revolt by Aristobulos' son, Antigonus, briefly conquers the area (supported by the Partians), Hyrcanus was exiled. But Antipater's son, Herod, appealed to Rome, which proclaimed him king. With Roman troops from Syria he conquered Judea, and became king.
Then after his death you get to where you said you knew, where things are divided up, and eventually Judea becomes a province.
The main source on this is Josephus, a 1st century historian. This narrative specifically is in the first book of Wars of the Jews. It's a bit of a confusing read, though. Which is really unavoidable, since the story of exactly how things pass from the Hasmonean dynasty to the Herodian (but under Roman control) is quite complicated.