The consul Quintus Caecilius Metellus is sent to North Africa to defeat Jugurtha.

Metellus is honest and able as a commander but is buying time in order to maximize his glory when he does actually defeat Jugurtha.

His successful war plan is to destroy Jugurtha's supply lines and this forces Jugurtha to guerilla tactics.

Drusus had been elected censor along with the elder Marcus Aemilius Scaurus in 109 BCE, but had died the following year.

Gaius Marius, ordered to replace Metellus (given the title "Numidicus" for his efforts, although he has accomplished precisely nothing in his time there) and prosecute the war in Numidia, disregards standing recruitment qualifications and regularizes the recruitment of the landless poor, thus transforming the citizens’ militia into a professional army.

The Roman forces are again unable to subdue Jugurtha, despite Metellus’s policy of laying waste to the Numidian countryside.

An internal Roman struggle develops between Metellus and his subordinate commander (legate), Gaius Marius.

Metellus permits Marius to return to Rome and Marius is elected consul in 107 BCE.

Metellus is fully aware of Marius' ambitions in Roman politics and refuses for days to allow him to sail to Rome and stand for the consulship.

Metellus is, however, unaware that Marius wants his command in Numidia.

Numidia is not an area designated to be protected by consul by the Roman Senate.

However, the populares pass a law in its Tribal Assembly, which gives the command against Jugurtha to Marius in 107 BCE.

This is significant because the Assembly has usurped the Senate's rights and powers in this matter and the Senate has yielded.

Aquilius, having completely subdued Salvius and his insurgents, receives a triumph in Rome in 100 BCE.

Gaius Marius, having gained his sixth term as consul, has meanwhile revised the organization, training, and equipment of Roman armies by the introduction of a volunteer, semiprofessional army, its ranks open to the proletarians or common people.

With the German invaders annihilated (a third horde of barbarians has turned away without troubling Rome), the proletarian soldiers who have accomplished the task clamor for more land, but Rome’s ruling oligarchy refuses to recognize their demands.

Consequently, coalitions begin to form between destitute veterans and ambitious generals.

The popularist tribune Lucius Appuleius Saturninus and the praetor Glaucia propose and pass liberal land laws assigning land in the province of Africa to Marius’s veterans.

However, the radical nature of these bills and the forcible methods Saturninus and Glaucia have used in ensuring their passage alienate a large part of the Roman people.

Metellus Numidicus, now well established as a conservative leader in the Senate, refuses to accept Saturninus' agrarian law, and is consequently exiled from Rome.

Numidicus’ son, Quintus Caecilius Metellus, helps achieve his father’s return to Rome in about 98, earning for himself the surname Pius (which means filial devotion).

Eventually even Marius had become alienated to the legislative methods employed by Saturninus and Glaucia.

As a result Saturninus’s laws are repealed, and the Lex Caecilia Didia is introduced as an attempt to reduce hasty legislation passed in the comitia.

Put into effect by the consuls Q. Caecilius Metellus Nepos and Titus Didius in the year 98 BCE, this law has two provisions.

The first is a minimum period between proposing a Roman law and voting on it, and the second is a ban of miscellaneous provisions in a single Roman law—what might, in modern terms, be called omnibus bills.

The goal is to curb the passage of radical bills, with the assumption that the period of trinundium will give the citizens time to understand the proposed law or to be persuaded to vote against it.

Publius Rutilius Rufus, who had started his military career in 134 BCE, as a member of the staff of Scipio Africanus Minor during the Numantine War, later became a legate of Quintus Caecilius Metellus Numidicus in the campaign against Jugurtha of Numidia of 109 BCE, along with Gaius Marius.

He distinguished himself in the battle of the Muthul, where he faced a charge by the foe Bomilcar and managed to capture or maim most of the Numidian war elephants.

He was in 105 BCE elected to the consulship as a senior partner of Gnaeus Mallius Maximus.

His main achievements concerned the discipline of the army and the introduction of an improved system of drill.

Subsequently, he served as legate to Quintus Mucius Scaevola, governor of Asia.

Scaevola, completing his reorganization of Asia, returns to Rome, leaving in Pergamon Rufus, who firmly applies the new principles they have established.

This causes an outcry from businessmen, whose profits Scaevola has kept within bounds.