In 142 BCE, Jonathan was assassinated by Diodotus Tryphon, a pretender to the Seleucid throne, and was succeeded by Simon Maccabee, the last remaining son of Mattathias. Simon gave support to Demetrius II Nicator, the Seleucid king, and in return Demetrius exempted the Maccabees from tribute. Simon conquered the port of Joppa, where the Gentile population were 'forcibly removed', and the fortress of Gezer. He expelled the garrison from the Acra in Jerusalem. In 140 BCE, he was recognised by an assembly of the priests, leaders and elders as high priest, military commander and ruler of Israel. Their decree became the basis of the Hasmonean kingdom. Shortly after, the Roman senate renewed its alliance with the Hasmonean kingdom and commanded its allies in the eastern Mediterranean to do so also. Although the Maccabees won autonomy, the region remained a province of the Seleucid Empire and Simon was required to provide troops to Antiochus VII Sidetes, the brother of Demetrius II. When Simon refused to give up the territory he had conquered, Antiochus took them by force.