Alexander the Great joins Julius Caesar, Genghis Khan and Napoleon as one of the great military conquerors in history.

Likewise, “Alexander” should join “Ishtar,” “Heaven’s Gate” and “Gigli” as one of the biggest cinematic bombs of all time.

“His failures tower over other men’s successes,” a rambling Ptolemy (Anthony Hopkins) says of the title character.

That same phrase can apply to writer-director Oliver Stone. The Oscar-winning filmmaker hits his career nadir with an embarrassing period piece that manages to be boring, overly long (3 hours), confusing, implausible and incapable of creating a single character who can engage the audience.

Stone had trouble finding an American studio that would fund this $150 million epic. (Warner Bros. is merely distributing it.) So Stone convinced the German company Intermedia Films to sink its entire fortune into his dream project.

It may prove to be the worst German strategic decision since the invasion of Russia in World War II.

Dark-haired Irish actor Colin Farrell is the natural choice to play the blond-haired Macedonian Alexander. Yet the swarthy Farrell (apparently borrowing Freddie Prinze Jr.’s wig from “Scooby-Doo”) is only the third most miscast person in the movie. The first is Angelina Jolie, who stars as Alexander’s witchy mother Olympias. It’s somewhat distracting that Jolie is only 11 months older than Farrell. It’s downright giggle-inducing that she pretends to be his mom without a hint of aging prosthetics or cosmetics.

Hey makeup department, couldn’t you have given her some crows feet or gray hair?

Then there is Val Kilmer, who portrays King Philip, Alexander’s one-eyed lout of a father. Stone previously culled a memorable turn from Kilmer in the otherwise annoying biopic, “The Doors.” Conveniently, Kilmer gives the same performance in “Alexander.” It could just as easily be the drunken, self-absorbed, borderline psychotic Jim Morrison seated on this Macedonian throne.

Colin Farrell stars as Alexander the Great in the action adventure drama 'Alexander.'

The film’s story follows Alexander’s (356-323 B.C.) rise to power following Philip’s assassination. Eventually the young king pits his armies against the Persian Empire, then spends years waging war in Egypt and finally India. His efforts spread Greek culture throughout Europe and Asia, somewhat uniting the region.

Stone takes this fascinating figure and reveals nothing about him. The actor’s dialogue (co-written by Stone, Christopher Kyle and Laeta Kalogridis) consists entirely of platitudes such as “Conquer your fear and I’ll promise you’ll conquer death” and “Fortune favors the bold.”

It’s a complete mystery what drives Alexander, the circle of friends and family who surround him (especially his innately hostile barbarian bride played by Rosario Dawson) or the men who follow him to the ends of the earth. These individuals look like they’re going through the motions of history that have been heaped upon them in retrospect by the filmmaker. At no point do any of them seem like actual people.

With its rampant homoeroticism, elaborate costumes and jumbled fight choreography, one would assume this is a Joel Schumacher flick not an Oliver Stone production. The only real hint the project is helmed by the director responsible for “Platoon” and “Natural Born Killers” is a few trippy snippets such as when the king is plagued by fever. Otherwise there is little about the film’s conceptualization that is distinctive.

If the picture had come out two years ago, a few of the scenes might have earned some points on the “spectacle” meter. But the infinitely better “Troy” already did the Bronze Age saga some justice earlier this year. And “The Lord of the Rings: The Return of the King” proved how to expertly craft large-scale warfare between an army on elephants and one on horseback — which is regrettably the same action climax of “Alexander.”

Considering so many recent movies have staged phenomenal battle sequences, it’s amazing that Stone — a veteran who’s participated in actual combat — manages to make them wholly uninvolving. The edits are too quick and there is never a clear sense of who is doing what. Both major action centerpieces imply Alexander’s troops are on the verge of being defeated, only to cut to a later scene where his armies are celebrating their victory.

It’s unlikely there will be much celebration in Stone’s camp after his dull behemoth drowns at the box office. He has succeeded in making the year’s worst film. In some respects, that truly is an epic achievement.