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

Alexander is a name used by five individuals in The Jewish Wars. The earliest Alexander was a son of John Hyrcanus. When John died, Alexander's oldest brother Aristobulus made himself monarch and put Alexander in jail with two other brothers. Aristobulus died less than a year later and his widow made Alexander monarch. Alexander executed one of his brothers but honored the only one left. Alexander continued to acquire land till he died twenty-seven years later when he left the throne to his wife Alexandra. A later Aristobulus was poisoned and had a son Alexander that was axed by Pompey's order. This Alexander had a daughter named Mariamme, who married Herod at the start of his reign. She had five children including two sons Aristobulus and Alexander that were accused of plotting against Herod. Caesar acquitted Alexander of the plot but Antipater, a half-brother encouraged tales about them that fed Herod's fears. Herod raged and put Aristobulus and Alexander in solitary confinement before he ordered them to be strangled and buried at the side of their grandfather, Alexander. Children of this executed brother named Alexander were sons named Tigranes and Alexander and a daughter Aris. Finally an imposter appeared who looked like and claimed to be Alexander that Caesar sent to the galley-slaves for claiming a false identity.