Fantastic Four (Vol. 4) #5
I Killed Julius Caesar!
Valeria and Franklin are putting on a show for the members of the Fantastic Four, telling a story about Julius Ceaser, who, according to the ancient accounts of Plutarch, was once captured by Sicilian pirates whom he later put to death. The Thing and the Human Torch are impressed by the story but wonder if that's how it really happened. Franklin points out that they will have the opportunity to ask him when they meet him, as they have travelled back to Earth circa the year 44 BC in order to study ancient Rome. Mister Fantastic and the Invisible Woman begin to steathily land their ship. Sue is still angry at Reed for keeping the fact that his powers are slowly killing him a secret from the others. Reed understands that she is angry at him, but he needs help to find a cure before he dies. Sue agrees to help, but points out she can still also be angry at him.
Soon the ship lands, and the children are reminded not to do anything that will have an impact on history. As such, the members of the Fantastic Four and the Richards children begin dressing in clothing that were common for the time period. In the case of the Thing, he is made to wear a massive robe that will disguise his outward appearance. Reed and Sue tell the Johnny and Ben to go out on the expedition alone, as they need "mommy-daddy time". While Johnny and Ben are able to read between the lines, both Franklin and Valeria are confused by what their parents mean. Soon, Johnny, Ben and the children have managed to use their various talents to con their way into meeting with Julius Ceasar. He tells them how his death has been foretold, but he doesn't believe that he can ever die. When they doubt his claim that he is immortal, Ceasar surprises them from reciting lines from the Willaim Shakespear play about him that will not be written some sixteen hundred years in the future.
Back aboard the ship, Reed explains that the decay began when he was bitten by the dinosaur in the ancient past. He goes on to tell her that he orchestrated this whole trip, under the guise of education for the children, to try and find a cure for himself. However, so far all their travels have done is taught him about how little he knows about the illness plaguing him. However, if Reed dies at least he has some comfort in dying by the people he cares about most. Sue tells Reed that she is disappointed that he kept this a secret from them all and tells him that he has no right to decide what he protects his family from. She gets him to admit that he can't fight this in secret and the two make up.
Back in Rome, the man claiming to be Julius Ceaser takes Johnny, Ben, and the children into a deep chamber where he surprises them with a space-time ship. Suddenly a strange pink smoke begins to issue forth from "Ceaser's" mouth and eyes. As it turns out, he is not Ceaser at all, and that the real Julius Ceaser has been dead for years. The alien explains that it too is an explorer of time and space and has spent its time studying Earth. Traveling back to this period, he witnessed how Julius Ceaser was thrown from a startled elephant he was riding and suffered a fatal blow to the skull in the fall, years before history stated he was to die. Seeing a time paradox in work, the alien tried to prevent it from happening by possessing Casear's body and making sure that he carried out his appointed history, this is how he knows of Caesar's death, and the fact that William Shakespeare will write a play about him. Ben and Johnny area against the idea of "Ceasar" allowing himself to get executed, but the alien explains that history must follow it's appointed course. No sooner do they leave the secret chamber are they surrounded by guards who take them into custody, setting in motion the events that will lead to the assassination of Julius Ceaser.
Back aboard the ship, Reed and Sue are doing laundry. When Sue complains about how the children's socks always seem to give out at the same time, she suddenly comes to a shocking realization. She asks Reed if what is happening to him might also happen to herself, Johnny and Ben.
Back in Rome, "Ceasar" is brought before Marcus Brutus who is fated to kill him, while Ben and the others are forced into the arena where they must fight Cacus the Son of Vulcan. As "Ceasar" is seemingly stabbed to death, the Thing clashes with Cacus. Suddenly, the Thing begins giving into his rage and beats their foe to a bloody pulp. So violent is the Thing, Johnny is disturbed and tells the children to look away from the fight. With the battle over, Ben assures Johnny that he is all right and suggests they return home. That evening, under the cover of darkness, they help smuggle "Julius" out of Rome. They rendezvous with Reed and Sue to tell them what happened and introduce them to "Ceasar". Thanking Johnny for helping him escape Rome, the alien formally known as Julius Cesear heads off into the world to start a new life.
.... Centuries later in modern-day New York City. The alien -- now a businessman named Mr. Cotta -- reads a newspaper story about the disappearance of the Fantastic Four. He goes to a secret room where he has been keeping his space-time ship. He decides to help this new Fantastic Four out because Caesar always repays his debts.
Continuity Notes
This is the first time it is revealed that Julius Ceaser was replaced with an alien. This story placed the death of the real Julius Ceaser as happening sometime in 49 B.C. As such, this makes the first appearance of the alien posing as Ceaser to be Incredible Hulk #210 which is the first time the murder of Ceaser is depicted in a Marvel story.
Cotta's encounter with the replacement Fantastic Four and the children of the Future Foundation is depicted in FF Vol 2 #9.