The Entire Battlestar Galactica Timeline Explained

In the fall of 2019, NBC announced its new Peacock streaming service would include a reboot of the science fiction franchise Battlestar Galactica. No cast was announced, but the news did name Mr. Robot creator Sam Esmail as the show's executive producer. After the announcement, fans wondered whether this new series was going to be a reboot or a sequel or something else, so Esmail took to Twitter to clear up some of the confusion. "BSG fans, this will NOT be a remake of the amazing series [Ronald D. Moore] launched because... why mess with perfection? Instead, we'll explore a new story within the mythology while staying true to the spirit of Battlestar. So say we all!"

The world of Battlestar Galactica spans hundreds of thousands of years. The original Battlestar Galactica first premiered in 1978, with a sequel series called Galactica 1980 following in 1980. A re-imagined Galactica premiered on Syfy in 2004 and ran for four seasons, offering up some compelling post-9/11 commentary on war and humanity along the way. It'll be interesting to see which themes this new series will address, but before it premieres, let's revisit the BSG timeline, and see where the latest Battlestar Galactica might fit in.

On a planet named Kobol, tens of thousands of light-years from Earth, a race of humans evolved and became the dominant species on their planet. They developed many of the same scientific advancements that we have on Earth — and went several steps further, creating artificial intelligence in the form of robots they used as slave labor. Eventually, the robots, named Cylons, rose up and rebelled against their human masters. Their war so devastated Kobol that humans and Cylons both abandoned it. The humans went on to colonize a separate system of twelve planets, while the Cylons settled on a planet they called "Earth."

On "Earth," the Cylons evolved until they became cybernetic humanoids ("skinjobs") and once again enslaved a race of mechanical, robotic Cylons, not learning from their history. Again, the robotic Cylons revolted against their masters, and an intense war was waged. During this time, a Cylon consciousness evolved to the point that it existed on a higher "software"-like plane, becoming an omniscient type of Cylon God.

After total nuclear destruction of "Earth," only five scientific researchers survived. They invented resurrection technology, which "downloads" their consciousness into a new, identical clone body. Knowing that the humans had since become the Twelve Colonies of Kobol, these "Final Five" Cylons made it their mission to find them and warn them that the past could repeat itself, and to treat their creations better. 

While the Final Five were making their way to the Twelve Colonies, the humans did indeed create their own version of artificial intelligence, robots that they enslaved and also called Cylons. The creation of these Cylon "Centurions" was detailed in Caprica, a prequel series that aired after Battlestar Galactica ended. In the series, men named Daniel Graystone and Thomas Vergis invent the cybernetic technology used to create the Cylon Centurions. Daniel's daughter, Zoe, is killed in a terrorist attack, but her consciousness is downloaded into a virtual world, and then placed inside one of the Centurions, creating the first sentient Cylon. This suggests the beginning of when the Centurions started to evolve, as Zoe's consciousness spreads through their system. Zoe's parents eventually make her a biological clone body, a "skinjob," and download her consciousness into it, but her essence, religious leanings, and sentience linger within the Cylons and spread to others.

The original 1978 Battlestar Galactica series also follows this Cylon rebellion on the Twelve Colonies — in essence, the third Cylon rebellion in history. That series isn't exactly a prequel to the 2004 series... but it isn't exactly not, either. Characters like Adama and Starbuck exist in the original and the reboot. But the original only takes place during a single Cylon War, whereas the reboot series references the First Cylon War as being 40 years prior to current events.

When the Final Five finally arrived at the Twelve Colonies, the humans and Centurions had already been at war for 12 years. The Centurions were experimenting with the creation of flesh bodies, "skinjobs," and had created the "Hybrids," the combination biological and cybernetic entities that pilot their ships. The Final Five offered the Centurions a deal: They would help the Centurions create their own flesh bodies if they abandoned their war with humans.

On the colonies, a few decades of peace followed. The Final Five helped to create the eight biological "skinjob" models of Cylon, but they still harbored resentment towards the human race. Model Number One, a.k.a. John Cavil, found it particularly difficult to let go of his anger, or of his jealousy for other models. He corrupted the Cylon model Number Seven, essentially making it extinct. He also turned on the Final Five, stealing their memories and banishing them into various points in the Twelve Colonies timeline, essentially making the Final Five humans who don't know their true identities. Cavil also took the memories of the other remaining six Cylon models and eventually convinced them to attack the humans again.

All the while, the godlike Cylon Entity observed, and created its own "messengers" to send to both humans and Cylons.

Forty years after the First Cylon War, the ship Galactica is about to be decommissioned, and its Commander, William Adama (Edward James Olmos), retired. The ship's crew includes second in command Colonel Saul Tigh (Michael Hogan), pilots Kara "Starbuck" Thrace (Katee Sackhoff) and Sharon "Boomer" Valerii (Grace Park), tactical officers Felix Gaeta (Alessandro Juliani) and Anastasia Dualla (Kandyse McClure) plus hangar deck officer Galen Tyrol (Aaron Douglas). Secretary of Education Laura Roslin (Mary McDonnell) and Adama's son Lee "Apollo" Adama (Jamie Bamber), another pilot, arrive on the ship for the ceremony. Meanwhile, on the planet Caprica, Gaius Baltar (James Callis), a famous scientist, is seduced by a Cylon in disguise (Tricia Helfer) and gives up security codes which allow the Cylons to attack, destroying the 12 colonies.

The attack leaves Galactica the last remaining human battleship, Roslin inherits the role of president, and a fleet of civilian ships survive under their watch. The whole fleet jumps away from their home system and heads out into space to search for the lost 13th Colony: Earth. Meanwhile, it's revealed that Boomer is actually a disguised Cylon, one of seven skinjob models who are able to re-upload themselves into new bodies if they're killed in action.

The fleet continues its evasion of the Cylon ships, jumping throughout space on their search for Earth. Starbuck proves herself to be a skilled but hot-headed pilot, earning a reputation for unruly behavior.

Galactica's Boomer begins behaving strangely, unaware that she's a Cylon. Another Boomer on Caprica seduces a pilot, Karl "Helo" Agathon, in an attempt to create a human-Cylon hybrid baby.

Back on the ship, Adama tasks Baltar with building a Cylon detector so they can weed out hidden Cylons. Baltar hallucinates his Cylon seducer, Number Six, who convinces him to sabotage the project and delay the reveal of his involvement. He uses the machine on Boomer, whose bizarre behavior and superhuman abilities have led others to suspect her of being a Cylon as well. But Baltar lies and says she passes the test. Boomer's ship then discovers a planet that could be Kobol, and Baltar and Tyrol are marooned there when investigating.

Roslin, who was diagnosed with breast cancer before the Cylon attack, begins taking a new drug that makes her hallucinate and she becomes convinced that they need to retrieve the "Arrow of Apollo," an ancient artifact that will help them find Earth, from a museum on Caprica. She sends Starbuck on a mission to find it and Starbuck reunites with Helo, who has discovered that his Boomer is a Cylon — and pregnant. The season ends with original Boomer, having learned that she's a Cylon, now activated, shooting Adama twice in the chest on the bridge.

Chaos reigns onboard Galactica. With Adama in sick bay, Boomer in the brig, and Roslin now believing herself to be some kind of prophet, Tigh declares martial law and some ships in the fleet break off from the group. Baltar and Tyrol are rescued from Kobol, while Dualla helps Roslin escape from her own imprisonment. But a disgruntled crew member shoots and kills Boomer, which leads to her consciousness being uploaded to a new body on a Cylon battleship nearby. Thankfully, Adama regains consciousness and brings some stability back to the crumbling society.

On Caprica, Starbuck and Helo take refuge with a group of resistance fighters led by Sam Anders (Michael Trucco), and Sam and Starbuck begin a relationship. Starbuck is kidnapped and taken to a Cylon fertility farm where they are harvesting human ovaries, but they're rescued by pregnant Boomer, now the only Boomer they know, and the group heads back to Kobol to reunite with Roslin.

As it turns out, Galactica wasn't the only Battlestar to survive the Cylon attack. The Pegasus, captained by Admiral Helena Cain (Michelle Forbes), finds their comrades, having been raiding Cylon ships ever since the destruction of the 12 Colonies. As an Admiral, Cain outranks Adama, and takes over the fleet, though not without some suspicion and mistrust from much of the Galactica crew.

On the Pegasus, a captured Cylon model number six named Gina is being interrogated, raped, and tortured by Pegasus crew members. Cain has Baltar interrogate her as well, and she reveals the existence of "Resurrection Ships," which allow Cylons to re-upload their consciousness into a new body.

The Pegasus, however, turns out to be a crew full of jerks. Helo and Tyrol prevent a Pegasus crew member from raping Boomer, accidentally killing another crew member in the process. Cain sentences them to death, but Adama refuses to hand out the punishment. Cain and Adama plot against one another, while Baltar cures Roslin's cancer with amniotic fluid from Boomer's fetus. Gina shoots Cain in the head, killing her, and sets off a nuclear bomb, destroying half the fleet.

The surviving members, including Galactica and Pegasus, now captained by Lee Adama, discover a new planet they name New Caprica. Baltar runs to replace Roslin, campaigning on colonizing a new world, and wins the presidency. Boomer gives birth to her baby, Hera, but is told that the baby has died, with Roslin planning on hiding the baby from the Cylons, lest they find out she exists and worship her.

The season ends jumping forward one year, with Baltar's presidency somewhat a failure, the Adamas running an orbiting fleet, Starbuck and Anders married, and Roslin gone back to teaching. But the Cylons finally discover their new planet, and the fleet jumps away to safety, leaving the planet alone for Cylon takeover.

Season 3 begins months into the Cylon takeover of New Caprica with the humans surviving as best they can. Colonel Tigh loses an eye in Cylon prison, then learns his wife was helping the Cylons, so he poisons her. Baltar tries to act as a liaison between humans and Cylons, but he's really just a puppet. Starbuck is being held prisoner by Leoben, Cylon model Number Two, in an apartment-like prison. He tries to win her affection, claiming that he's created a child using her harvested eggs, but Starbuck kills him repeatedly, only to have him resurrect in a new body.

Tyrol and Anders contact Galactica and Pegasus, who have been plotting a rescue mission on their own. Apollo, commanding the Pegasus, has gained a lot of weight and married Dualla. (Adama grew a mustache. Hey, everyone dealt with it in their own way.)

The rescue mission is successful, but the Pegasus is lost to incredible damage. Boomer, having turned on the Cylons, is renamed Athena, and she and Helo learn that their baby Hera is alive and captured by the Cylons along with Baltar. Helo kills Athena so she resurrects on the Cylon basestar, rescues Hera, and escapes with Baltar's Number Six (Caprica Six) back to Galactica.

Meanwhile, Cylon model Number Three, D'Anna, begins repeatedly killing herself and resurrecting because every time she dies she has visions of something called "The Final Five" — five other Cylon models that no one knew existed.

When the humans land on an algae planet to gather food supplies, Tyrol discovers the Temple of the Five, also known as the Temple of Hopes, which holds the "Eye of Jupiter," which will help them find Earth. The Cylons, having learned about the Final Five and the Temple through D'Anna's visions, find the humans and offer a truce if they give up the Eye, but Adama refuses.

The final few episodes of season 3 get a little chaotic, with Adama putting Baltar on trial, Apollo coming to his defense, and the humans jumping away to safety but seemingly giving up on finding Earth. Roslin's cancer returns. Starbuck, who's been acting strangely, flies off in a daze following an invisible Cylon raider, but her ship gets caught in atmospheric pressure and crushed. Starbuck is presumed dead... for a while, that is.

In a major finale twist, four of the Final Five are revealed. Tyrol, Anders, Tigh, and Roslin's aid, Tory Foster, all begin hearing music in their heads. They hum along to a plinky plunky version of "All Along the Watchtower" and meet each other secretly in a hangar deck, fully realizing who they are. Cylons!

In the season's final moments, the fleet is attacked once again by Cylon forces. When Apollo and the other viper pilots seem like they're about to be blown to bits, Starbuck's plane suddenly appears. She tells Apollo over the com that she's been to Earth and knows how to get there.

With Starbuck back from the dead, all hell breaks loose. Humans turn against humans and Cylons against Cylons. Baltar becomes the center of a monotheistic religion and recruits followers. Apollo joins the Quorum of Twelve. Civil war breaks out among the Cylons, with the Number Ones, Fours, and Fives turning against rebel Number Sixes, Twos, and Eights. The rebels want to wake up Number Three (D'Anna) who had been boxed after her repeated suicides.

The rebels team up with the humans. In exchange for helping the Cylons fix one of their ships, rebooting D'Anna, and finding the Final Five, the humans can destroy the Resurrection Hub, the ship controlling all Cylon resurrections, thus making them mortal. When Roslin visits the stranded ship to talk with its Hybrid, the Hybrid reboots and jumps away, taking Roslin, Baltar, and a number of humans.

The team successfully destroys the Resurrection Hub and wakes up D'Anna, reuniting back with the fleet. There's an intense standoff among the humans and Cylons, with D'Anna demanding to know the whereabouts of the Final Five (she's seen them in her visions) which leads to Tyrol, Tigh, Tory, and Anders revealing themselves as Cylons. In the ensuing chaos, Starbuck's viper emits a signal, finally leading them to Earth. The humans and Cylons agree to investigate, only to find the planet completely destroyed — a nuclear wasteland irradiated long ago.

The human and Cylon alliance is devastated. With "Earth" a nuclear wasteland, they have no potential home and no further answers to their questions. As they explore "Earth," Starbuck makes an alarming discovery: her own ship, crash-landed on the planet with the charred remains of a body that looks exactly like her. She died in the crash, apparently, but was brought back to life, leading her and others to wonder if she is the fifth and final Cylon.

As the fleet tries to find a new homeworld, Ellen Tigh is revealed as the final Cylon, but she's kept prisoner by Cavil and the vengeful Number Ones. Cavil also kidnaps Hera, the human-Cylon hybrid. The fleet plans a rescue, but Galactica is damaged beyond repair. The Final Five eventually remember everything about their past: "All this has happened and will happen again." A semi-comatose Sam Anders is hooked up to Galactica as its own Hybrid, and an epic Battle of the Colony ensues, with Cavil and the "bad" Cylons finally defeated. 

Adama orders Starbuck to make a "blind jump" to anywhere in space, and she uses coordinates that line up with a drawing of Hera's and the musical notes from "All Along the Watchtower." They land on Earth — real Earth — and decide to stay and live simple lives, without their advanced technology. Sam steers Galactica and the rest of the fleet into the sun. Starbuck disappears, having been one of the Cylon Entity's "Messengers," and Roslin dies in Adama's arms. The surviving humans and Cylon, including Helo, Athena, and Hera, begin their new lives on Earth.

In an epilogue, the story jumps 150,000 years into the future — a future that looks exactly like our present. Battlestar Galactica didn't take place in the future at all, it was set in Earth's past. Humanity's past. Our past. The scene is New York City, and the camera pans up from the planes of Africa to Central Park. The Cylon Entity Messengers that resemble Baltar and Caprica Six stroll through the crowd, unseen by others, and talking to each other about Earth's new discovery, as detailed in a National Geographic magazine. Apparently, new fossils have been found supporting the theory that all human life on the planet can be traced back to one most recent ancestor, a single "Mitochondrial Eve, or a first woman, who lived in Tanzania. "Along with her Cylon mother and human father," Baltar finishes, suggesting that Hera is the Mitochondrial Eve that can be considered Earth's mother. 

As they walk, Six and Baltar discuss how Earth has repeated the history of Kobol, Earth One, and Caprica before it. Consumerism, mass use of technology. "All this has happened before and will happen again," Six says. But they wonder, does it have to happen again? Six bets not, saying that a repeated cycle has to change at some point, and it's all a part of God's plan. "You know it doesn't like to be called that," Baltar says. The two smile and walk away. 

As the series ends, Jimi Hendrix's version of "All Along the Watchtower" plays as we see footage of artificial intelligence, robots, and humans interacting with robots, suggesting maybe it will happen again after all.