I am taking my first foray into world building for an upcoming campaign. I am going to start small and local and build out from there, but I did want to have some larger backdrop concepts in place as well.  Instead of multiple large continents, I have decided on a world that is made up of many smaller islands - the largest will be just a tad larger than Britain.  Demographics will be standard fantasy races, and I am toying with the idea of having each race having a homeland (island) that they originated from (although some may have migrated from there since - haven't made up my mind on that,though).

With this said, my question is this.  What would be the logical implications of having an island world on cultures, races, politics, religion, magic, trade, etc. that may not be so evident on a world with larger continents?  Off the top of my head I came up with these themes:

-Migration.  There should be cultures that migrate due to catastrophe, exploration or conquest.
-Religion:  Definitely a god of trade and the sea.
-Pirates!
-Many calendars will be moon based due to the effect of the tides on culture.
-Creation myths will be ocean based.
-Prominence of merchant class and traders (guild)
-And increased effect of xenophobia

Any other ideas?

And here is the original map created in FT3.  I have a ways to go in editing it as i want to shape it a bit.

Well, off the top of my head:

1. Navigation will be far more common and important. Maybe not everyone will be the equivalent of a Polynesian sailor, but many will be.
2. Likewise, shipbuilding and boat building skills will be more common.
3. More spells related to purifying water, cooking food without flame, drying things out (or people simply wont care about being wet.)
4. The sea offers freedom and the chance to disappear quickly. If navigation, boat building and sea survival are more common then it will be more difficult to be a dictator and control a population. I'm not saying democracy and civil rights are going to be the norm, but rulers will be less harsh if people can easily pick up and go.
5. Any kind of protected port area will be more valuable.
6. Access to the best forest zones will be critical too. Wood = boats. Lots of wood = lots of boats. Lots of boats = lots of power and wealth.
7. You will have to decide what kind of technologies are prevalent. Is the whole world like Polynesia, with smaller canoe sized craft on the oceans? Are there Greek and Persian style triremes roaming the coasts? Viking sized ships crossing the seas? Giant Chinese junk style ships? Or are you planning 17th century type of frigates? All of the above?
8. With fewer large land masses hurricanes would dissipate less (land tends to be the death of them.) You might want to decide where and when (what time of year) hurricanes commonly form and how they travel. There are websites where you can see common hurricane tracks to get an idea. And remember, they don't have to be just a northern hemisphere phenomena either. (Hurricanes normally start near the equator, but not on it, then bend off toward the poles.)
9. What creates the land masses? Volcanoes or continental plates upthrusting the land? Maybe the gods are doing it.
10. Animals are difficult to transport on the oceans. They also evolve in isolation from each other. Meaning: not every land will have horses, or donkeys or camels. A minor predator on one land can be a major one on another. See for example the brown snake problem in the Pacific.

There's a good start for you.

Great stuff - this is exactly what I was looking for:

1. Yes!
2. Got it
3. Good point.  This makes me think of have some sort of "Wind Weaver" and Water Warden" class/specialty.  And now that I think about it (and off of your suggestion) maybe have some sort of limitation on magic similar to Earthsea - you have to be proficient in the local area to cast fully.
4. Great point
5. Amen
6. Good call.  The lumber trade should be a big element.
7. Technology will be early to late iron age - travel will be risky and the best knowledge/skill in ship building will be coveted and fought over.
8. Another great point
9. All three : )
10. One of the best points of all.  Especially since dragons are going to be a strong element and don't like to fly over open water in the setting.  Kinda gives a reason for the different colors/metals.

Thank you!

And here is the first pass at editing. Still planning on softening some of the crescent shape land forms...but half time is almost over for the Patriots : )

There won't be any large migratory animals that develop naturally, since there aren't any large plains or steppes. Island dwarfism and gigantism would be fun for setting up island themes.

Weapons and armour would definitely edge towards the light side, due to several factors, limited access to metals, the need to make sure you can swim, so you can't have stuff that's too heavy or you'll drown.

Bare handed styles may also be common, as weapons would likely serve double duty as a tool of some sort.

Quote from: Christopher Brady;857930Weapons and armour would definitely edge towards the light side, due to several factors, limited access to metals, the need to make sure you can swim, so you can't have stuff that's too heavy or you'll drown.

Bare handed styles may also be common, as weapons would likely serve double duty as a tool of some sort.

Or no armor at all if the boats are small or the oceans known to be storm-tossed.

Battle oars, like a wooden axe or spear may be in use.

Since these are islands. Metal may be hard to come by since you might not be able to mine too deep due to the water table or vulcanism. This may make wooden weapons more common. And a sharpened wood blade is just as deadly.

If there is volcanic activity then obsidian may be a viable blade edge. Especially if it can be re-inforced with magic. Hello Vorpal Blade.

You might end up with fantastical things like a large man-made island like a giant raft, or built from a collection of smaller homes. Or the ever popular monster turtle island. Air power might develop instead of boats. Hot air balloons, magic propelled gliders, zepplins. Or things could go Silent Service style with fantasy submarines.

Weather is going to be a major factor. How often are storms and how big do they get? What defenses, if any, are there?

Increased xenophobia isn't necessarily a logical consequence. There could just as easily be a cosmopolitan seafaring culture binding together different islands.

The Polynesia expansion and cultural anthropology would be a rich resource to mine for ideas as well as Indonesia and the Philippines.

My general impression is

1) Long distance sea voyages wasn't a barrier for low tech cultures. In lieu of the compass, sextant it relied on a deep understanding of how wind and currents worked for a region as well as reading the signs for nearby land.
2) There was a minimum island size/resource base for long term in habitation. Below that settlement existed but were depended on trade for survival. I.e. the settlement had something worth enough to trade to bring in the missing resources.
3) There doesn't appear to be any reason for any particular type of culture NOT to exist. For example Japan had epic feudal warfare on the scale that Europe had.
4) Despite #1 there are some barriers that would be near impossible to cross on a regular basis. For example the divide between Indonesia and Australia.

Off the top of my head, and presuming we're talking realism here ...

* With an eyeballed scale on that map, presuming that the largest island is Britain-sized, you don't need Polynesian sailor-level navigation, not remotely close.  Those distances are, in many cases, within sight lines, and those long atoll shapes would prove very forgiving of inaccuracies.

* Wood is indeed critical, and you've got a big problem with that: the Pacific island cultures suffered a number of ecological disasters related to population booms and deforestation, and especially with bigger and badder hurricanes, once you've stripped the forests, they ain't never coming back.  You might want to tinker with a (possibly religion-based) conservationist mentality.

* Another problem you're going to run into is a relative lack of metals.  Between that and wood being a finite and coveted resource, ship sizes are going to be nowhere remotely close to Age of Sail tonnage.  (Beyond that, smaller ships are much easier to beach when the aforementioned giant hurricanes come through.)

Get youself a copy of Collapse: How Societies Choose to Fail or Succeed by Jared Diamond.  That should help quite a bit.

A European ship during the Age of Sail & Exploration took aboard a chief from a South Pacific island and sailed him off to SE Asia. The chief was consistently able to point the direction back home, despite not using any equipment or calculations. Earth animals, including humans who haven't forgotten how, seem to have some unexplained natural navigation abilities.

Island people are often not particularly xenophobic.

The indigenous island religions that come to mind tend to have their islands and land terrain features, and the sun and moon, as gods, as well as sea gods and animal gods (give or take in specific examples). In one case, the whole world (their island - they didn't go to others, and weren't upset when Dutch anthropologists showed up to hand out with them) is their mother god, and they live on its decaying dead body, and the universe has a regenerative cycle where it all happens again... which it turns out was more or less accurate, as they lived on a shield volcano island chain.

Quote2) There was a minimum island size/resource base for long term in habitation. Below that settlement existed but were depended on trade for survival. I.e. the settlement had something worth enough to trade to bring in the missing resources.

The minimum size isn't particularly large, though. If the weather's nice, you just need enough food and shelter and (particularly) fresh water.

Quote3) There doesn't appear to be any reason for any particular type of culture NOT to exist. For example Japan had epic feudal warfare on the scale that Europe had.

Yes, and heavy armor and steel weapons despite not much iron, and not much seafaring.

As for animal evolution, that depends too on what the land masses used to look like. Since you're using Fractal Terrains software, you can easily see for example what happens if you lower the water level, and/or raise some of the sea floors. There may have been a period not that long ago where many or most of the islands, or certain groups of them, were connected and included more plain areas, so those might share land animal species and the later island populations might include animals that had evolved on a different landscape. I.e. there could be some plains animals from when there were plains, as well as some animals that might naturally die off on an island, but got domesticated. E.g. there are Pangean animals both in the Americas and in Europe/Africa/Asia, such as deer, wolves, bears...

A huge thanks to everyone who has chipped in - this is exactly the stuff I was looking for!  I am not looking for uber-realism (otherwise I'd be playing in Harn), but would still like some semblance of consistency. I especially like the following points:

Armor - Although heavy armors will be available, there prevalence will be much reduced
Weapons - Like armor, outside of the larger islands, a preference will be on light weapons
Metal - The point about scarcity of metal is a great theme.  Those who have the access and skill to craft these items will be praised and paid.  I am thinking of giving this honor to the dwarven clan - logical holders of this prized knowledge.  I also like the parallel idea of the use of obsidian - especially when magically imbued.
Xenophobia - While I will grant that xenophobia does not naturally follow from island societies, especially one's based on trade, I do think there is a justification for isolated areas where the fear of strangers would be logical - especially areas were past attempts at colonization/conquering has occurred and failed or had a negative impact on the native culture.
Scarcity of Materials - This is a great theme.  And the Eco-terrorist Druid idea is pure gold.
Ship Size and Design - Great point.  I am thinking of giving one race primacy in ship building, and leaning towards Orcs for an interesting spin.

And here is an updated map.

Some thoughts.

If these are smaller Easter Island style islands with a more aboriginal theme and smaller boats then armour is going to be rare to non-existent due to the severe dangers. There may be little incentive to develop more than leather, padded, or equivalents. Metal armors are about out as its a death sentence.

Larger islands will be a different matter. But then a large England or Japan scale island you can have extensive adventures and never see the ocean once. Armour there will be whatever level you want that fits your idea of the setting limits.

Quote from: Omega;858114Some thoughts.

If these are smaller Easter Island style islands with a more aboriginal theme and smaller boats then armour is going to be rare to non-existent due to the severe dangers. There may be little incentive to develop more than leather, padded, or equivalents. Metal armors are about out as its a death sentence.

Larger islands will be a different matter. But then a large England or Japan scale island you can have extensive adventures and never see the ocean once. Armour there will be whatever level you want that fits your idea of the setting limits.

Yeah, unless you're having at least one island the size of Japan, any sort of actual metal will likely be pressed into tools or weapons, but likely both.  At the same time.  Like boat hooks and small axes.