Alexander Jannaeus was the second king of the Hasmonean dynasty, who ruled over an expanding kingdom of Judaea from 103 to 76 BCE. A son of John Hyrcanus, he inherited the throne from his brother Aristobulus I, and married his brother's widow, Queen Salome Alexandra. From his conquests to expand the kingdom to a bloody civil war, Alexander's reign has been described as cruel and oppressive with never-ending conflict. The major historical sources of Alexander's life are Josephus's Antiquities of the Jews and The Jewish War.

The Hasmonean dynasty was a ruling dynasty of Judea and surrounding regions during the Hellenistic times of the Second Temple period, from c. 140 BCE to 37 BCE. Between c. 140 and c. 116 BCE the dynasty ruled Judea semi-autonomously in the Seleucid Empire, and from roughly 110 BCE, with the empire disintegrating, Judea gained further autonomy and expanded into the neighboring regions of Perea, Samaria, Idumea, Galilee, and Iturea. The Hasmonean rulers took the Greek title basileus ("king") as the kingdom became a regional power for several decades. Forces of the Roman Republic intervened in the Hasmonean Civil War in 63 BCE and made it into a client state, marking the decline of Hasmonean dynasty; Herod the Great displaced the last reigning Hasmonean client-ruler in 37 BCE.