Passage: To varying degrees throughout Roman history, the existence of a pool of inexpensive labor in the form of slaves was an important factor in the economy. Slaves were acquired for the Roman workforce through a variety of means, including purchase from foreign merchants and the enslavement of foreign populations through military conquest. With Rome's heavy involvement in wars of conquest in the 2nd and 1st centuries BC, tens if not hundreds of thousands of slaves at a time were imported into the Roman economy from various European and Mediterranean acquisitions. While there was limited use for slaves as servants, craftsmen, and personal attendants, vast numbers of slaves worked in mines and on the agricultural lands of Sicily and southern Italy.For the most part, slaves were treated harshly and oppressively during the Roman republican period. Under Republican law, a slave was not considered a person, but property. Owners could abuse, injure or even kill their own slaves without legal consequence. While there were many grades and types of slaves, the lowest—and most numerous—grades who worked in the fields and mines were subject to a life of hard physical labor.This high concentration and oppressive treatment of the slave population led to rebellions. In 135 BC and 104 BC, the First and Second Servile Wars, respectively, erupted in Sicily, where small bands of rebels found tens of thousands of willing followers wishing to escape the oppressive life of a Roman slave. While these were considered serious civil disturbances by the Roman Senate, taking years and direct military intervention to quell, they were never considered a serious threat to the Republic. The Roman heartland had never seen a slave uprising, nor had slaves ever been seen as a potential threat to the city of Rome. This would all change with the Third Servile War.

Question: How much of a threat did the large civil disturbances pose to the Republic?
never considered a serious threat