Why did the Roman Senate refuse to approve Pompey’s eastern settlement as a whole?

The Roman Senate’s refusal to approve Pompey’s eastern settlement as a whole was primarily driven by the political opposition of the Optimates, an inner ring of nobles who sought to curb Pompey’s growing power and prestige upon his return to Italy in 62 BCE.1

Key factors contributing to this obstruction included:

• Political Rivalry: Influential figures such as Lucius Licinius Lucullus and Marcus Porcius Cato the Younger were determined to prevent Pompey from consolidating his influence through the en bloc ratification of his arrangements.1
• Land Demands: The Senate specifically resisted Pompey’s demand for land grants to settle his veterans, which was a central component of his proposed settlement.12
• Institutional Jealousy: The nobility, having reasserted their dominance in Rome, viewed Pompey’s extraordinary success and his status as a "first citizen" with suspicion. They feared his potential to act as a revolutionary and sought to block his efforts to secure further large-scale services to the state.1

This obstructionist stance eventually pushed Pompey to form the First Triumvirate with Julius Caesar and Marcus Licinius Crassus to bypass the Senate's resistance.34