currently in Iceland, I’ve been thinking about this. As of now there are 330,000 people in Iceland. According to the wiki page on the Icelandic commonwealth medieval Iceland had a population of around 50,000 (but this number is unsourced). When danish records began in the early 1700’s Iceland’s population was still just 50,000. That’s due to the little ice age, Danish trade monopoly, volcanic eruptions, Turkish raids etc. However I’m pretty sure we can keep Iceland’s population growing (though I don’t know by how much) if we can tame some of these elements. Let’s say that there’s a Danish commitment to developing Iceland. They decide to set up ports in Iceland as trading posts, attracting some migration, and allow the local population to trade for food with everyone (limiting the effects the little ice age had on agriculture). If we decide to, we can just hand wave the volcanic eruptions away, though that feels kinda like cheating. Barring any weird stuff (like settling all the Jews who are expelled from European countries in Iceland) how large can we get Iceland’s population to be? Is 1 million realistic? I’m pretty sure the modern island can support that, you just need a large enough premodern starting population.