Grainger, John D. The Decline and Fall of the Ptolemies. Ptolemaic Egypt 146-30 BC

After the death of Ptolemy VI, his younger brother Ptolemy VIII took over as king. This was the beginning of a long, albeit interrupted, turbulent period of family disputes, punctuated by rebellions, conspiracies and wars. One king, Ptolemy VII, was assassinated, Ptolemy VIII's two wives plotted and rebelled, and when he died, one of them, Cleopatra III, was his actual successor. Ptolemy VIII was not a bad king in some respects and encouraged the exploitation of the discovery of the monsoon climate in the Indian Ocean to develop trade with India, and he used his (much reduced) fleet to maintain contact with the countries of the Mediterranean. Cleopatra III made another attempt to reconquer Palestine, but this failed (Eighth Syrian War). Ptolemy IX was the last legitimate Ptolemy, and the succession was constantly disputed from then on. And the rising power of Rome hovered over everything. It had been largely absent from the eastern Mediterranean until the Mithradatic Wars repeatedly brought its power to the east. Egypt was gradually drawn into the spell of the Roman Republic, primarily as a source of money to finance the wars and the greed of the Roman aristocracy, until the last Ptolemy, Cleopatra VII, sided with Marcus Antonius and was defeated by Octavian's troops.