49 BC: Caesar Defies the Senate, Enters Roman Italy Under Arms

The Roman Republic in 50 BC (yellow), after the Conquest of Gaul. Germania Libera (Free Germany) is shown in pink.(source)

49 BC Julius Caesar, Praefect of Gaul, defies the Roman Senate by crossing the Rubicon river towards Rome with a legion, thus leaving his province (Cisalpine Gaul) and illegally entering Roman Italy under arms.

In 50 BC, the Senate, led by Pompey, ordered Caesar to disband his army and return to Rome because his term as governor had finished. Caesar thought he would be prosecuted if he entered Rome without the immunity enjoyed by a magistrate. Pompey accused Caesar of insubordination and treason. In January 49 BC, Caesar crossed the Rubicon river (the frontier boundary of Italy) with only one legion and ignited civil war.

Upon crossing the Rubicon, Caesar, according to Plutarch and Suetonius, is supposed to have quoted the Athenian playwright Menander, in Greek, "the die is cast". Erasmus, however, notes that the more accurate Latin translation of the Greek imperative mood would be "alea iacta esto", let the die be cast.

Pompey and many of the Senate fled to the south, having little confidence in his newly raised troops. Despite greatly outnumbering Caesar, who only had his Thirteenth Legion with him, Pompey did not intend to fight. Caesar pursued Pompey, hoping to capture him before his legions could escape

50 BC Roman conquest of Gaul completed.

54 BC Marc Antony, age 29, gains a position on the military staff of Julius Caesar.

58 BC Julius Caesar, during his conquest of Gaul, describes encountering the Suebi, a Germanic people living north of the Alps.

"The Suebi actually occupied more than half of Germania, and are divided into a number of distinct tribes under distinct names, though all generally are called Suebi, Classical authors noted that the Suevic tribes, compared to other Germanic tribes, were very mobile, and not reliant upon agriculture.

Various Suevic groups became a periodic threat to the Roman Empire on its Rhine and Danube frontiers. Caesar placed the Suebi apparently near modern Hesse, in the position where later writers mention the Chatti, and he distinguished them from their allies the Marcomanni. Caesar describes the Suebi as pressing the German tribes of the Rhine from the east, forcing them from their homes."

60 BC Julius Caesar proclaimed imperator by the Roman Senate.

62 BC Julius Caesar appointed to govern Hispania Ulterior (modern south-eastern Spain) as propraetor. He conquers two local tribes there, extending Roman rule in Iberia, and is acclaimed imperator by his troops. "He reformed the law regarding debts, and completed his governorship in high esteem."

Imperium is a Latin word which, in a broad sense, translates roughly as 'power to command'. In ancient Rome, different kinds of power or authority were distinguished by different terms. Imperium referred to the ability of an individual to command the military. 

In the Roman Republic, imperator was an honorary title assumed by certain military commanders. After an especially great victory, army troops in the field would proclaim their commander imperator, an acclamation necessary for a general to apply to the Senate for a triumph. 

63 BC (Sept. 23) Birth of Gaius Octavius (Augustus). He is the great-nephew of Julius Caesar, through his mother. Although his paternal family was from the town of Velletri, approximately 25 mi from Rome,  Augustus was born in the city of Rome, at a small property on the Palatine Hill called Ox Head, very close to the Roman Forum.

63 BC Julius Caesar, age 36, wins election as Pontifex Maximus, chief priest of the Roman state religion. 

He ran against two powerful senators. Accusations of bribery were made by all sides. Caesar won comfortably, despite his opponents' greater experience and standing. Cicero was consul that year, and he exposed Catiline's conspiracy to seize control of the republic; several senators accused Caesar of involvement in the plot

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Statue of Strabo in his hometown (modern-day Amasya, Turkey), beside the Iris (Yeşilırmak) River

64 BC (circa)  Strabo (Στράβων) is born to a Greek family in Pontus. On his mother's side, he was descended from a prominent family whose members had held important positions under the resisting regime of King Mithridates VI of Pontus.

89–85 BC First Mithridatic War. Roman conquest of the Pontus.

146 BC Roman conquest of the peninsula of Greece.
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146 BC Roman sack and complete destruction of Carthage at the end of the Third Punic War. End of the Carthaginian Empire.

168 BC Third Macedonian War. Romans conquest of the Macedonian kingdom.

168 BC Romans conquest of Illyricum is completed, by defeating the army of the Illyrian king Gentius.

206 BC Roman conquest of the Carthaginian colonies in Iberia.

Theatre of the Second PunicWar  showing Carthaginian and Roman territory (source)

217 BC Second Punic War. First Roman expedition to Iberia.

218 BC Roman conquest of Italy completed.

229 BC First Illyrian War. First Roman naval crossing of the Adriatic.

264-241 BC First Punic War. Rome conquers Sicily from Carthage.

280-275 BC The Pyrric War. Rome and Carthage repel an invasion by the King of Epirus.

387 BC Rome sacked by Gauls.

396 BC Rome conquers the neighboring city of Veii.

439 BC Second dictatorship of Lucius Quinctius Cincinnatus.

458 BC First dictatorship of Lucius Quinctius Cincinnatus.

Cincinnatus was regarded by the Romans, especially the aristocratic patrician class, as one of the heroes of early Rome and as a model of Roman virtue and simplicity. He was a persistent opponent of the plebeians.When his son, Caeso Quinctius, was convicted and condemned to death, Cincinnatus was forced to live in humble circumstances, working on his own small farm, until an invasion caused him to be called to serve Rome as dictator, an office which he resigned two weeks later, after completing his task of defeating the rival tribes of the Aequians, Sabines, and Volscians.

501 BC Titus Lartius named the first Roman dictator, with purpose of organizing the city against impeding war with the Sabines. Lartius relinquishes powers after six month term. (see List of Roman dictators).

Lartius' first consulship was in 501 B.C., the ninth year of the Republic. His colleague was Postumus Cominius Auruncus. During their year of office, there was a disturbance at Rome, which was attributed to the actions of a group of young Sabines. Only the previous year, the consul Spurius Cassius Viscellinus had defeated the Sabines near Cures, and for a while it appeared that the war might be rekindled. Tensions were also high because it was anticipated that war with the Latins was imminent. Octavius Mamilius, the prince of Tusculum, and son-in-law of Lucius Tarquinius Superbus, the seventh and last King of Rome, was forming an alliance amongst the thirty towns of Latium, with the aim of restoring Tarquin to the throne.

In these circumstances it was decided to appoint a single magistrate, originally called the praetor maximus or magister populi, "master of the infantry", but afterwards known simply as the dictator, to oversee the defense of the city. The dictator held supreme authority in the exercise of his duties, and the people had no right to appeal from his decisions, as they could under the consuls. However, the command of the dictator was limited to a period of six months. The Senate directed the consuls to nominate a dictator, and Cominius chose his colleague, Lartius. The dictator then proceeded to nominate Spurius Cassius, who had triumphed over the Sabines the previous year, as his magister equitum, or "master of the horse".

The creation of this magistracy is said to have alarmed the Sabines, who sent envoys to Rome in order to avert war. The negotiations were unsuccessful, and war was declared, but both sides were reluctant to take the field, and no battle occurred. During the remainder of his office, Lartius held the census, negotiated with the various Latin towns in hopes of retaining some old allies and gaining new ones, and presided over the consular elections for the following year. He then laid down his office before the expiration of his term, setting a precedent for future dictators.

The appointment of a dictator involved three steps: first, the Senate would issue a decree known as a senatus consultum, authorizing one of the consuls to nominate a dictator. Technically, a senatus consultum was advisory, and did not have the force of law, but in practice it was nearly always followed. Next, if both consuls were available, either could nominate a dictator, either by agreement, or if they could not agree, by drawing lots Finally, the Comitia Curiata would be called upon to confer imperium on the dictator through the passage of a law known as a lex curiata de imperio.

501 BC First consulship of Lartius.

502 BC The consul Spurius Cassius Viscellinus defeats the Sabines near Cures.

509 BC Founding of the Roman Republic. The Romans expel the last Etruscan King, Tarquin the Proud. Abolition of the monarchy and the establishment of the Consulship.

The imperium, or executive power, of the king was divided between two annually-elected magistrates, known as praetors. In time they would come to be known as consuls. Consuls had extensive powers in peacetime (administrative, legislative and judicial), and in wartime often held the highest military command

Two consuls were elected each year, serving together, each with veto power over the other's actions, a normal principle for magistracies.  The insignia of the Consuls were the toga praetexta and the sella curulis, and each was attended by an escort of twelve lictors, each of whom bore the fasces, a bundle of rods topped by an axe; but by custom the lictors had to remove the axes from their fasces within the pomerium, the sacred boundary of Rome, to signify that the people, and not the consuls, were sovereign.

It is thought that originally only patricians were eligible for the consulship.  Consuls were elected by the Comitia Centuriata, which had an aristocratic bias in its voting structure which only increased over the years from its foundation.

Map of Latium in the 5th century BC. (source)

753 BC Founding of the city of Rome with Romulus as king. Founding of the Roman Senate, as an advisory body to the king.  Origin of the reckoning of the traditional Roman  calendar, ab urbe condita (AUC).