Gaius Julius Caesar (circa 100 BC - March 15, 44 BC) was a Roman military leader and dictator. His military conquest of Gaul extended the Roman Empire to the Atlantic Ocean, an achievement whose consequences are visible to this day. His establishment of a government under the First Triumvirate (see below) brought the Roman Republic to an end. He later became Dictator for Life and began many reforms in Roman society and government, work that was cut short by his assassination. Many of these reforms were later implemented by Augustus Caesar. Caesar's military achievements are known to us in detail from his own written accounts.
Caesar's family was not rich by the standards of the Roman nobility[?], and no member of his family had achieved any outstanding prominence in recent memory, though in his father's generation there was a renaissance of their fortunes. His paternal aunt Julia married Marius, the leader of the Populares against the influence of the Optimates. Also, Caesar married Cornelia, daughter of Lucius Cornelius Cinna in 84 BC. This family relationship, with political involvements, caused Caesar great trouble during the dictatorship of Sulla, who ordered him to divorce in 82 BC; Caesar refused and prudently left Rome for military service in Asia and Cilicia. He was back in 78 BC, when Sulla died, and began his political career as a prosecuting advocate.
He travelled to Rhodes for philosophical studies, and on the way was kidnapped by pirates. He convinced his captors to raise his ransom, which increased his prestige in Rome. After he was ransomed, he organised a naval force, captured the pirates and put them to death by crucifixion.
Having held the positions of quaestor in Spain[?] (69 BC), Caesar was elected curule aedile in 65 BC, pontifex maximus in 63 BC, and praetor in 62 BC. If it is true that he was implicated in the Catiline conspiracy, it did him no lasting damage.
Caesar had already been in the service of the general, Pompey, with whom he would later share power. Following the death of his wife Cornelia (68 BC), he married Pompeia, granddaughter of Sulla, only to divorce her in 62 BC after a scandal. In 61 BC, Caesar served as governor of the province of Hispania Ulterior, and in 60 BC he was elected consul.
In 59 B.C., the year of his consulate, Caesar entered into a strategic alliance with two other leading politicians, Marcus Licinius Crassus and Gnaeus Pompeius Magnus. Crassus was the richest man in Rome; Pompey was the most successful general. Caesar brought to the alliance his political popularity and drive. Pompey married Caesar's daughter Julia. This unofficial alliance is called by historians the First Triumvirate, or "rule by three men." The Triumvirate meant the end of the Roman Republic.
In 59 BC he was also governor of Gaul and Spain. As Proconsul in Gaul from 58 BC - 49 BC he waged war against various peoples, defeating the Helvetii in 58 BC, the Belgic confederacy[?] and Nervii in 57 BC and the Veneti in 56 BC. In 55 BC he attempted an invasion of Britain. In 52 BC he defeated a union of Gauls. His accounts of these campaigns were recorded in Gallic Wars.
Crassus having been killed in 53 BC fighting the Parthians, a rift developed between Caesar and Pompey. Called upon by the senate in 50 BC to disband his army, Caesar refused and civil war broke out. A soothsayer named Alex Spampano warned Caesar of his conquest. He was told to be wary of the Rubicon. Caesar crossed the Rubicon on January 10, 49 BC (iacta alea est - meaning that "the die is cast") and pursued Pompey to Brundisium, hoping to patch up their deal of ten years before. Pompey eluded him, however, and Caesar made an astonishing 27-day route-march to Spain to knock out Pompey's lieutenants in Spain. He then went back east, to challenge Pompey in Greece. Having finally defeated Pompey at the Pharsalus, Greece, in 48 BC, he was given a five-year term as consul, whilst Pompey fled to Egypt, where he was murdered by an officer of King Ptolemy XIII of Egypt.
Not content with the advantage he had gained, Caesar went on to Egypt, where he involved himself in upholding the rule of Cleopatra, who became his wife (under Egyptian law, but not Roman). He then proceeded to defeat Pompey's remaining supporters at Tapsus (46 BC) and Munda (45 BC).
Given a ten-year term as consul in 46 BC, he was made dictator for life in the following year, and was called Father of his Country (Pater Patriae). The month of Quintilis was re-named in his honour, and continues to be known as July.
The question of whether or not Caesar intended to accept the title of King, to settle for the title of Dictator, or even to escape from the question by leaving for the Eastern Mediterranean to fight the Parthian Empire causes scholarly debate. It is certain, however, that his apparent arrogance and ambition brought him great unpopularity and the suspicion of his peers.
Caesar was assassinated in the Theatre of Pompey (where the Senate met after the Senate House was burnt down in a recent incident), on the Ides of March of 44 BC. He was stabbed by a group of conspirators who believed in preserving the republic against his alleged monarchical ambitions. Among these was Caesar's adopted son, Marcus Junius Brutus. Caesar fell at the feet of a statue of Pompey and his famous last words are variously reported as:
After Caesar's death, a power struggle broke out among his great-nephew and adopted son Octavianus, his chief lieutnant Mark Antony and his assassins Brutus and Cassius. Octavianus prevailed and became the first Roman emperor, taking the name Augustus Caesar.
His surviving oeuvre of writings, however, place among the greatest masters of Latin prose style - these comprising his accounts of the wars in Gaul (de bello Gallico) and of the civil war against Pompey and the senate (de bello civili). These narratives, apparently simple and direct in style, are in fact highly sophisticated advertisements for his political agenda, most particularly for the middle-brow readership of minor aristocratic persons in Italy and the provinces of the Empire.
Secondly his 'Commentarius' on the Civil War, against the forces of Pompeius and the Senate, viz. *De Bello Civili  (http://digilander.iol.it/jackdanielspl/Cesare/bellocivili), about the civil war (49 BC) and Caesar's refusal to obey to Senate (Rubicon's crossing)
Contemporary accounts of some of Caesar's other campaigns:
The name Caesar remained in many languages as a synonym and a title of commander, leader; the German Kaiser and the russian czar titles are derived from the name Caesar, as were several subsequent Roman emperors. It has to be remembered that Latin classical pronunciation for Caesar sounded like "kai-sahr".
The root itself may not be of Latin origin: on the Rosetta Stone there is a hieroglyphic cartouche that has been transcripted as k-e-s-r-s and supposed as related to the Latin sense. More interesting, it has been said that Latin Caesar could be a derivation of the Persian Kasrá=Chosroës and its plural form Akásirah (the title of four great dynasties of Persian Kings[?]), through Ahasuerus or Khshayarsha (Xerxes I, grandson of Cyrus the Great); eventual relationships with kisri and kasra have been seen as less meaningful, also because mostly referred to later times (Sassanides[?]).
Note: the name Gaius is completely equivalent to Caius, so Caesar's name is found in both forms.