The Worlds of Foundation: A Guide to the Planets Between Trantor and Terminus

Asimov's galaxy has 25 million inhabited worlds, and the Foundation novels name only a few dozen of them. Most of those names appear once or twice: a kingdom that threatens Terminus, a planet where a trader lands, a waypoint on a long journey. Taken together, though, they trace the whole arc of the saga, from the first Settler colonies of the Robot novels to the Foundation's last search for Earth.

This guide covers the smaller worlds, in roughly the order the story reaches them. The major settings have their own pages: Trantor, Terminus, Anacreon, Aurora, Solaria, and Gaia. You can also find every world on the interactive galaxy map.

Baleyworld: The First Settler World

Robot and Empire era. Later renamed Comporellon.

At the end of the Robot novels, humanity faces a choice. The fifty Spacer worlds, long-lived, rich, and dependent on robots, have stopped expanding. Earth is crowded and poor, and its people have lived so long inside enclosed cities that most are afraid of open sky. Elijah Baley's great argument, carried through The Robots of Dawn and Robots and Empire, is that Earth's people must go out and settle new worlds themselves, without leaning on robots the way the Spacers do.

Baleyworld is where that argument became real. It was the first world of the new wave of "Settlers," founded by Baley's son Bentley and named in the detective's honor. Baley himself later left Earth to join the Settlers.

The Settlers bred fast, used few robots, and expanded quickly. Within a few centuries they far outnumbered the Spacers, and the galaxy that became the Galactic Empire grew out of their expansion, not the Spacers'. Baleyworld is therefore a kind of starting line for everything in the Foundation novels.

Comporellon: The World That Remembered

Foundation era. Appears in Foundation and Earth (1986).

Twenty thousand years later, Baleyworld is Comporellon, a cold, conservative planet near the Sayshell sector that is loosely tied to the Foundation Federation. It claims to be the oldest inhabited world in the galaxy, and its folklore still remembers a founder called "Benbally," a worn-down echo of Ben Baley.

Golan Trevize, Janov Pelorat, and Bliss go to Comporellon first when they set out to find Earth in Foundation and Earth. They are detained on arrival and have to bargain their way free, but a local historian gives them what they came for: the coordinates of three of the ancient Spacer worlds, Aurora, Solaria, and Melpomenia. Those coordinates set the course of the rest of the novel.

Comporellon's role is quiet but important. Across the galaxy, records of Earth have vanished so completely that most scholars treat it as a myth. On this one old world, the story survived in a garbled form, and that was enough.

Smyrno: One of the Four Kingdoms

Early Foundation era. Appears in Foundation (1951).

When the Empire pulls back from the Periphery around 50 F.E., the old Anacreon province breaks into four independent kingdoms: Anacreon, Smyrno, Konom, and Daribow. Terminus sits in the middle of them, and none of them has nuclear power.

Smyrno is a hot, dry world, and its people live underground. It is Anacreon's rival rather than its equal. In "The Encyclopedists," Salvor Hardin's answer to Anacreon's threat depends on that rivalry: he persuades the other three kingdoms that none of them can let Anacreon alone take over Terminus and its technology.

Smyrno comes back a century later in a more personal way. Hober Mallow, the Master Trader who resolves the third Seldon Crisis, was born a Smyrnian, and his political enemy Jorane Sutt uses that background against him. On Terminus, Smyrnians are looked down on as provincial and untrustworthy, which makes Mallow's rise to the mayor's office all the more pointed. See the full Hober Mallow profile.

Korell: Where Trade Beat Force

Merchant Princes era, about 155 F.E. Appears in Foundation.

The Republic of Korell is a republic in name only; its ruler, the Commdor Asper Argo, holds power by inheritance. Korell bans the Foundation's missionaries outright, so the religion of science that kept Anacreon in line has no grip there.

When Foundation trading ships start disappearing near Korell, Hober Mallow is sent to investigate. He finds that Korell has modern atomic weapons, and he follows their trail to Siwenna, where he learns that a remnant of the Galactic Empire is still alive nearby and supplying Korell with warships.

The resulting war is the third Seldon Crisis, and Mallow wins it without a battle. Korell's people have come to rely on Foundation-made goods that they cannot repair or replace. When war cuts off trade, those goods break down, the Korellian middle class turns against the war, and Korell gives up. It is the clearest demonstration in the trilogy that economic dependence can be stronger than guns. You can play through this crisis yourself in the Seldon Crisis game.

Siwenna: The Empire's Edge

Merchant Princes and General eras. Appears in Foundation and Foundation and Empire (1952).

Siwenna is an old Imperial province on the Empire's fringe, and it links two stories a generation apart. In "The Merchant Princes," Hober Mallow meets the aging patrician Onum Barr there and sees how badly Imperial rule has decayed. In "The General," Onum's son, Ducem Barr, meets Bel Riose, the Empire's last great general, and explains to him why psychohistory says his campaign against the Foundation cannot succeed. The Apple TV+ series brings Ducem Barr and Siwenna into its second season.

Haven: The Traders' Stronghold

Mule era. Appears in Foundation and Empire.

By the time of the Mule, the Foundation's Independent Trading Worlds resent the rule of Terminus, and Haven is their center. Toran Darell grew up there, and Toran and Bayta return there after the Mule's rise. Haven cannot hold out once Terminus falls, and its surrender is one more step in the Mule's astonishingly fast conquest. In the TV series, Haven is where Toran's uncle Randu shelters the Mallows.

Kalgan: The Mule's First Prize

Mule era and after. Appears in Foundation and Empire and Second Foundation (1953).

Kalgan is a pleasure world ruled by a warlord when the Mule appears, and it is the first world he takes. It becomes the base of his Union of Worlds. Decades after the Mule's death, Kalgan's ruler, Lord Stettin, tries to recreate that empire and goes to war with the Foundation, and the teenage Arkady Darell ends up on Kalgan in the middle of that conflict. In the Apple TV+ series, the Mule's seizure of Kalgan opens Season 3.

Tazenda and Rossem: The False Trail

Mule era. Appears in Second Foundation.

Tazenda is where the Mule comes to believe the Second Foundation is hiding. His agents, the Converted Han Pritcher and the unconverted young Bail Channis, follow the trail to Rossem, a barren farming world that Tazenda rules. Rossem seems to hide nothing at all, and that is exactly the point.

The trail is false. Channis is secretly a Second Foundation agent, and the "knowledge" that led him to Tazenda had been planted in his mind to mislead the Mule. The Mule, who has been tracking his agents in secret, unmasks Channis and announces that his fleet has already destroyed Tazenda. He then forces Channis to "admit" that the real Second Foundation is on Rossem. At that moment the First Speaker of the Second Foundation, who is never named in the novel, appears. Neither Tazenda nor Rossem was ever the Second Foundation, and while the Mule's attention was fixed there, Second Foundation agents were undoing his Conversions across his empire. In the Mule's moment of despair, the First Speaker reaches into his mind and adjusts his emotions. The Mule returns to Kalgan and rules peacefully until his death about five years later. The real Second Foundation was on Trantor all along; see Star's End.

The Apple TV+ series gives Rossem a new role as the Mule's childhood home.

Sayshell: The Gateway to Gaia

Late Foundation era. Appears in Foundation's Edge (1982).

Sayshell is the capital of the Sayshell Union, a small independent state that has stayed outside the Foundation Federation for centuries even though Federation territory surrounds it. It even escaped the Mule's Union of Worlds. Its culture leans toward mysticism and a respect for nature that the scientific Foundation finds strange, and its legends say its founders came from no other known world, which is why Pelorat suspects it was settled directly from Earth.

Trevize and Pelorat go to Sayshell in Foundation's Edge because Pelorat has heard of a world called Gaia somewhere in the Sayshell sector. They find the stories are true, and that ships which go looking for Gaia do not come back.

The truth, revealed later in the novel, is that Sayshell's long independence was never luck. Gaia lies inside Sayshell territory and has quietly protected it. When Mayor Harla Branno brings a Foundation fleet to Sayshell's border, Gaia's influence steers the encounter into a harmless trade agreement.

Melpomenia: The Dead Library

Late Foundation era. Appears in Foundation and Earth.

Melpomenia is the third Spacer world on Comporellon's list, and the grimmest. Its atmosphere has almost entirely gone. In spacesuits, Trevize and his companions find an ancient library with a plaque listing all fifty Spacer worlds and their coordinates. On the way out they notice a moss growing on the seals of their suits, feeding on tiny leaks of carbon dioxide, and they destroy it before it can hitch a ride off the planet. Plotting the fifty worlds shows them a rough sphere, and Earth should be near its center.

Alpha: New Earth

Late Foundation era. Appears in Foundation and Earth.

The last stop before Earth is Alpha, an ocean planet orbiting Alpha Centauri A, the nearest star to the Sun. The Empire began terraforming it as a refuge for Earth's people after Earth became radioactive, but the project was never finished. A small population lives on a single island and calls their world New Earth.

The islanders are welcoming, but they intend to infect the visitors with a disease so that no one will carry word of their world back to the galaxy. A local woman who has grown fond of Trevize warns them in time, and they escape. From Alpha, the Sun is close enough to find. Earth itself turns out to be dead and radioactive, and the journey ends on its Moon, with R. Daneel Olivaw.

Alpha Centauri is not one of the fifty Spacer worlds, and nothing in the novels suggests it was settled early. Its importance is that it was humanity's refuge at the very end of Earth's story, not its first step outward.

How the Worlds Fit Together

Read in order, these planets tell the saga's history in miniature. Baleyworld is the start of the Settler expansion that produced the Empire. Smyrno, Korell, and Siwenna show the Empire's edges breaking apart and the Foundation rising in the gap. Haven, Kalgan, Tazenda, and Rossem belong to the Mule and the Second Foundation's answer to him. Sayshell, Comporellon, Melpomenia, and Alpha are waypoints on the last and longest search in the series, the search for Earth, which ends by tying the Foundation back to the Robot novels where it began.