In the beginning, when people lived in growing, unorganized communities of farms and villages, they may have thought the world was a shape other than spherical. Maybe they didn’t think of it at all. Why should they?
Considering how several ancient civilizations were avid astronomers, we could easily imagine they had creative ideas about the world and maybe its shape. That the Mayans or Egyptians even asked what shape the land might be is not a given. They may have asked a thousand other questions, and if they were oriented around time or the spirit world, not space or the material world, they may not have asked the question.
Dr Josho Brouwers of Bad Ancient takes up this question, saying once people began to explore the world, it became apparent we live on a globe. By the time Plato was writing, it was a common question, the assumption being in favor of a spherical planet. Aristotle proposed the Earth and all of the heavens were fixed in spheres, each inside the other.
Brouwers writes, “This idea – that the world was spherical – became pervasive in the Hellenistic period. The work of Aristarchus of Samos [310-230 BC], the first known scholar to argue that the earth revolved around the sun instead of the other way around, assumes that the earth was round.”
There’s even a suggestion that the educated of ancient India believed the world was spherical too. So, ancient scholars worked out and believed the world was a globe and the medieval church did not oppose them. The idea that Columbus wanted to prove the world was round (and other silliness about the medieval world believing in flatness) is something pushed by people with a beef against the church.