145 B.C.E. to 44 B.C.E.
At the time of 145 B.C.E. Rome had vast wealth and land but at the end of the 3rd period the republic collapsed. In Rome's final years they still had many wars. Rome's allies didn't want to pay Roman taxes and wanted to get a citizenship. in 91 B.C.E some of them revolted against Rome, to stop this they let Italians become Roman citizens. Rome also had many slave revolts as with there new lands they brought hundreds of thousands of slaves. Even though some slaves had respect, most were treated poorly. One many revolted and in one instance thousands of revolting slave were killed on the cross. The mood of people in Rome was not good either as many people and labors were unhappy. Generals who's armies were famous fought for power in Rome. Around 80 B.C.E., 200,00 Romans died in a civil war. After 40 years there was another civil war between two generals; Pompey and Julius Caesar. By the time Julius Caesar got power, Rome controlled most of the Mediterranean and much of Europe. In the year 49 B.C.E Pompey was back in Rome and he convinced the senate to not let Caesar come back to Rome with his army. Caesar knows disobeying the law would mean war, but if he came back with no army he would be killed so he took his army by crossing the Rubicon. The scared senate made him dictator and with this power he made the poor happy, gave thousands of jobs to Romans and established gladiator fights. Caesar wanted Rome to be a great empire. He gave citizenship to the people of Gaul and Spain but was killed on march 15 44 B.C.E. Fellow senators stabbed him 23 times while he was entering senate. This will evidently cause Rome to change from a Republic to an Empire.
*All units are in B.C.E., Not up to scale*