The following is a look at how the members of the First Triumvirate, Crassus, Pompey, and Caesar, died.
Crassus (c. 115 - 53 B.C.) died in one of Rome's embarrassing military defeats, the worst it suffered until A.D. 9, when Germans ambushed the Roman legions led by Varus, in Teutoberg Wald. Crassus had determined to make a name for himself, after Pompey had upstaged him in the handling of the slave rebellion of Spartacus. As the Roman governor of Syria, Crassus set out to extend Rome's lands eastward into Parthia. He was not prepared for the Persian cataphracts (heavily armored cavalry) and their military style. Relying on the numerical superiority of the Romans, he assumed he would be able to conquer whatever the Parthians might throw at him. It was only after he lost his son Publius in the battle that he agreed to discuss peace with the Parthians. As he approached the enemy, a melee broke out and Crassus was killed in the fighting. The story goes that his hands and head were cut off and that the Parthians poured molten gold into Crassus' skull to symbolize his great greed.
Here is the Loeb English translation of Cassius Dio 40.27:
27 1 and while Crassus even then delayed and considered what he should do, the barbarians took him forcibly and threw him on the horse. Meanwhile the Romans also laid hold of him, came to blows with the others, and for a time held their own; then aid came to the barbarians, and they prevailed; 2 for their forces, which were in the plain and had been made ready beforehand brought help to their men before the Romans on the high ground could to theirs. And not only the others fell, but Crassus also was slain, either by one of his own men to prevent his capture alive, or by the enemy because he was badly wounded. This was his end. 3 And the Parthians, as some say, poured molten gold into his mouth in mockery; for though a man of vast wealth, he had set so great store by money as to pity those who could not support an enrolled legion from their own means, regarding them as poor men. 4 Of the soldiers the majority escaped through the mountains to friendly territory, but a part fell into the hands of the enemy.
Pompey (106 - 48 B.C.) had been the son-in-law of Julius Caesar as well as a member of the unofficial power union known as the first triumvirate, yet Pompey retained the backing of the Senate. Even though Pompey had legitimacy behind him, when he faced Caesar at the Battle of Pharsalus, it was a battle of Roman against Roman. Not only that, but it was a battle of Caesar's terrifically loyal veterans against Pompey's less time-tested troops. After Pompey's cavalry fled, Caesar's men had no problem mopping up the infantry.
Then Pompey fled.
He thought he would find support in Egypt, so he sailed to Pelusium, where he had learned Ptolemy was making war against Caesar's ally, Cleopatra. Pompey expected support.
The greeting Ptolemy received was less than he expected. Not only did it fail to give him honor, but when the Egyptians had him in their shallow water vessel, safely away from his sea-worthy galley, they stabbed and killed him. Then the second member of the triumvirate lost his head. The Egyptians sent it to Caesar, expecting, but not receiving thanks for it.
Caesar (100 - 44 B.C.) died on the infamous Ides of March in 44 B.C. in a scene made immortal by William Shakespeare. It is hard to improve on that version. Earlier than Shakespeare, Plutarch had added the detail that Caesar was felled at the foot of the pedestal of Pompey so that Pompey might be seen to preside. Like the Egyptians vis a vis Caesar's wishes and Pompey's head, when the Roman conspirators took the fate of Caesar into their own hands, no one consulted (the ghost of) Pompey about what they should do with the divine Julius Caesar.
A conspiracy of senators had been formed in order to restore the old system of the Roman Republic. They believed that Caesar as their dictator had too much power. The senators were losing their significance. If they could remove the tyrant, the people, or at least the rich and important people, would regain their rightful influence. The repercussions of the plot were badly considered, but at least there were many illustrious fellow men to share the blame should the conspiracy go south, prematurely. Unfortunately, the plot succeeded.
When Caesar went to the theater of Pompey, which was the temporary location of the Roman Senate, on that March 15 day, while his friend Mark Antony was detained outside under some specious ruse, Caesar knew he was defying the omens. Plutarch says Tullius Cimber pulled the toga from the seated Caesar's neck as a signal to strike, then Casca stabbed him in the neck. By this time, the senators not involved were aghast, but also rooted to the spot as they watched the repeated dagger strikes until, when he saw Brutus coming after him, he covered his face to be more seemly in death. Caesar's blood pooled around the statue's pedestal.
Outside, chaos was about to begin its interregnum in Rome.