But it was under the reign of his brother Alexander Jannaeus, who ruled from 103-76 B.C.E., that the Hasmonaean dynasty reached the zenith of its power.

Alexander Jannaeus broke with previous policy and freely declared himself both high priest and king. The conflicts between the Hasmonaeans and the Pharisees intensified, even leading to a civil war in which 50,000 Jews perished. After the rebellion was quelled, in an act reminiscent of pagan kings, Jannaeus had 800 of the rebels impaled. In their dying moments, their wives and children were slaughtered before their eyes, while Jannaeus feasted openly with his concubines.b

Despite his enmity toward the Pharisees, Jannaeus was a pragmatic politician. He saw that the Pharisees had increasing popular support. His deathbed instruction to his wife, Salome Alexandra, was to share power with them. Jannaeus had chosen her over his sons as successor to his kingdom.