Founder of the Hasmonean Dynasty

Simon Thassi was a Jewish leader of the Hasmonean dynasty, serving as high priest, military commander, and ruler of Judea. The second son of the Hasmonean patriarch Mattathias and one of the Maccabean brothers, he assumed leadership after his brother Jonathan Apphus was captured by the Seleucid general Diodotus Tryphon. Simon played a central role in consolidating Hasmonean rule: he strengthened Judea's fortifications, expelled the Seleucid garrison from Jerusalem, and expanded Jewish settlement, laying the foundation for the Hasmonean state. His rule marked the beginning of effective Jewish independence.

Simon assumed leadership in 143 BCE, completing Jerusalem's fortifications and securing key areas, including Gezer and the port city of Jaffa, where he stationed Jewish garrisons and settled Jewish inhabitants. He defended Judea from Tryphon's forces and recovered his brother Jonathan’s body for burial at Modi'in. Simon consolidated Judea's independence, cultivated relations with Rome, Sparta, and the Seleucid Empire, and was granted rights such as tax exemption and coinage, though he may not have used them. In 142/141 BCE, he captured the Acra fortress in Jerusalem, removing the last remaining Hellenistic presence in the city. A public assembly formalized his rule as high priest, military commander, and national leader of the Jews, with hereditary succession in his family "until a new prophet should arise."

Simon was assassinated in 134 BCE at the fortress of Dok near Jericho by his son-in-law Ptolemy ben Abubus. His third son, John Hyrcanus, escaped and succeeded him, continuing the Hasmonean dynasty and expanding Judea's borders.