The Seleucid Empire was tearing itself apart, and Jonathan knew exactly how to exploit it. Josephus records that after Alexander Balas overthrew Demetrius I and claimed the Syrian throne, both rival kings competed to buy Jonathan's loyalty. Demetrius offered him the right to raise an army and reclaim Jewish hostages held in the citadel. But Alexander outbid him with a prize no Seleucid had ever offered a Jew: the High Priesthood itself.
Jonathan put on the sacred vestments at the Feast of Tabernacles. A guerrilla fighter in the wilderness had become both the military commander and the spiritual leader of his people. When Demetrius tried to counter with even more extravagant promises, the Jewish people rejected him. They remembered that Demetrius and his father had brought nothing but misery to Judea. They cast their lot with Alexander, and with Jonathan.
Alexander honored Jonathan lavishly. At his royal wedding in Ptolemais, where he married Cleopatra, daughter of Ptolemy Philometor of Egypt, Alexander seated Jonathan beside him on the throne, dressed him in royal purple, and publicly forbade anyone to speak against him. Jonathan had gone from hunted rebel to the most favored ally of the king of Syria.
When Demetrius's son, Demetrius II, arrived from Crete with mercenaries to reclaim his father's throne, his general Apollonius challenged Jonathan to come down from the mountains and fight on open ground. Jonathan responded by taking 10,000 soldiers to Joppa, which shut its gates against him. He stormed the city, then marched to meet Apollonius at Ashdod. The Seleucid general set a cavalry ambush, but Jonathan held his ground for hours until Simon led a charge that broke the enemy line. The fleeing soldiers took refuge in the temple of the idol Dagon at Ashdod. Jonathan burned the temple and the city around it.
But Jonathan also fought a quieter battle. He sent ambassadors to Rome and to Sparta, renewing old alliances and establishing the Jewish nation as a recognized power in the Mediterranean world. Josephus preserves the actual texts of these diplomatic letters, in which the Romans ordered that any enemies of the Jews should be handed over to Jonathan for punishment.
Jonathan's luck finally ran out when the cunning general Trypho lured him to Ptolemais with a small escort, promising friendship. Once inside the city, Trypho's soldiers slaughtered Jonathan's men, seized Jonathan himself, and later executed him. He had held power for nineteen years, building the Hasmonean dynasty from a band of fugitives into a sovereign state.