Final answer:
The Roman Senate began as an advisory body and grew to have significant power over legislation, investigations, treasury, and foreign affairs, influencing how other nations perceived the Roman government. Its role expanded from advising magistrates to being a dominant political force, especially in foreign policy, until its decline in the later stages of the Empire.
Step-by-step explanation:
The excerpt you are asking about describes the powers and roles of the Roman Senate during the Roman Republic. This Senate had a substantial influence over both domestic policy and foreign affairs. Initially an advisory council, the Senate grew in authority, eventually obtaining the power to propose laws and control the treasury. Over time, the Senate's ability to direct government spending made it a dominant force in Roman politics. As it decided on the use of public money, controlled investigations into crimes, and oversaw foreign policy, including the sending of diplomats to negotiate peace or declare war, many foreign rulers saw the constitution of Rome as an aristocracy because they mostly dealt with the Senate in their interactions with the Roman state.
The Senate began as a mere advisory body but expanded its power, assuming an essential role in the Roman government. It particularly influenced foreign policy and balanced out the powers of popularly elected bodies - an aspect that Baron Montesquieu's ideas of checks and balances in the U.S. Constitution later mirrored. Furthermore, after their terms in office, Roman elected officials typically became senators for life, giving the Senate a continuity and power beyond that of transient political figures. Despite its influence and prestige, the Roman Senate's power eventually waned with the end of the Republic and the rise of the Empire, with significant loss of authority under the reforms of Diocletian in the third century CE.