OSR: The Shape of the World

My current game is set in the not-14th century. The world is largely unmapped and the campaigns are largely local.

I was thinking about maps, and time, and worldbuilding. Most settings have spherical worlds. Some experiment with discs or toruses.

How To Be A Sailor - 1944

Here's an early world map, drawn in 1502. It's one of the earliest maps to show the world in a format we'd recognize.

Cantino Planisphere - 1502

Here's the map redrawn in a simplified format.

Fairly simple, right? Cold to the north, cold to the south, water to the east, and who knows what to the west.

And eventually, people circle around west and end up in the east and the world is finally confirmed to be round, despite the protests of clever people who say it's been confirmed round for centuries because of math. The top bit is cold, the bottom bit is cold, and the middle bit is warm.

And that's all fine and dandy, but what if it's not true? What if the world isn't a sphere or a disc or a flat plane?

What it's a spiral?

In 1520, Magellan tries to cut south across the tip of South America and reach the Pacific. Instead, he runs into ice. After weeks of storms and backtracking, with no stars visible, he finds a wide navigable channel. He follows it south.

And after weeks of ice and bitter cold, Magellan's crew spots mammoths. A shore party is attacked by a sabre-tooth tiger. Giant beasts unknown to the explorers are seen on the shore.

The survivors return home, disappointed and deeply confused.

Later expeditions don't help. Eventually, all the people with clever math and theories about the shape of the world toss out their models and redraw their maps.

The Time Spiral
Graham, Joseph, Newman, William, and Stacy, John, 2008

The world is a spiral. The diagram above is literal.

Upstream there is only ice, as far as anyone knows. Arctic explorers are trying to see if there is an upstream passage.

But downstream, the world changes. You can sail there and bring back treasures. You can also be devoured by dinosaurs. Whoever made the world didn't count on sailing ships. A few strays won't cause any issues - this explains coelacanths and crocodiles, they crept into our region from a past age - but an organized expedition seems to be a new concept.

It's not easy. Each "segment" on the spiral diagram is, essentially, a new continent or set of continents. Some are separated from others by ice sheets, channels, volcanic fields, ash dunes, or glass deserts.

In the Age of Discovery, the past is literally an unknown country.

But...
"But what about eclipses, Skerples?"
Yeah well what about eclipses?