Please bear with any confusing explanations – this is my first question on here.

I’ve started building a fantasy world with the rough geography and technological advancement of late 14th –15th century Europe. I've attempted to research resource production in this period, but I've been unable to find an answer I could make sense of and apply to my specific case.

My story is focused around an island off the Southern coast of the continent with a climate similar to that of Italy or Southern France – think hot summers and warmer winters, but with plenty of rain to keep crops growing. They’ve got two central forested mountains from which they’ve been mining gold for three hundred odd years, but most of the island is rolling plains with woodland here and there. In my head it’s roughly half the size of Northern Ireland.

(At least, that’s what I’m hoping. If the logistics don’t work I’m more than willing to change all of this.)

For my plot to work, the family that owns this island need to be rich – one of the richest in the country in fact, as the king wants to marry their daughter mostly for their wealth.

The gold mine helps with that, but it’s not consistently fruitful, and past years of scarcity have led the family to diversify into other areas. They also grow vines and make some of the best wine to be found anywhere, and breed a small number of very fine horses that they sell almost exclusively to the royal stables. These are enterprises for which they’re famed, but due to their high quality-low yield preference, I don’t think it will make them enough to keep them on the “Forbes Richest List”!

For their main area of income, I’d like the island to be one of the “breadbasket” areas of the country, who supply grains and vegetables and fruits primarily to the capital (on the coast almost directly north of the island, pop. 1million**) and other nearby towns and cities. They’re not the sole provider to those areas, but they do contribute a significant enough percentage that the capital would face food shortages if the island was to stop supplying food for whatever reason – say 5% of general food, but more like 15-20% of the nobility’s food as they favour the “exotic” fruits the island can provide.

Is it feasible for an island of my envisioned size (c. 7,000km2) and climate to supply that amount of food?

Would I be better off bumping up their gold mining, horse breeding and wine production and having them grow only enough food to supply their own population (c. 50,000 people)?

Please feel free to ask me to clarify anything I’ve explained poorly.

** EDIT: Thank you to all who've pointed out that this population is too high. I've phrased this poorly and meant to say that the 1 million population is that of the capital and towns and cities along that southern coast combined. This is still too high, so I'm going to reduce the overall number to 700,000 to be more in line with recommendations below.

  • $\begingroup$ Welcome to WorldBuilding Elle! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Commented Mar 27, 2018 at 15:08
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    $\begingroup$ Europe, 15th century, and a city of 1 million inhabitants. Does not compute. Anyway, basic rule of thumb is that with pre-industrial agriculture, good land and good climate you can feed 4 people per hectare, of which two are employed in working the land; that a surplus of 200 people per square kilometer. To feed that extra 1 million people you need the food grown on 5000 square kilometers. To support that cultivated land you need land for pasture, forests, etc. $\endgroup$
    – AlexP
    Commented Mar 27, 2018 at 17:24
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    $\begingroup$ You may want to consider that 15th century technology was not really conducive to transporting and distributing large quatities of bulky, heavy and low-value goods such as food. Almost all food was grown locally, within, let's say, 50 miles of the point of consumption. In no historical period ever did a country or region become rich by exporting staple foods. You want the island to export expensive wine, or spices which don't grow elsewhere. For example, make it the only place in the world where the fabled silphium of the ancients still grows. $\endgroup$
    – AlexP
    Commented Mar 27, 2018 at 18:28
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    $\begingroup$ "14th-century Europe", "family that owns the island", "half the size of Northern Ireland" -- sounds to me like you've got a member of the upper nobility there. $\endgroup$
    – Mark
    Commented Mar 28, 2018 at 0:35
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    $\begingroup$ @Mark That's my plan for them, I wasn't sure if it was relevant to the question so left it out of the original post but they are intended to be one of the prominent noble families of my world. $\endgroup$
    – Elle
    Commented Mar 28, 2018 at 15:51

5 Answers 5


What you actually need to make that Fortune 500 (maybe not 500, far fewer people) is a specialized product that can't come from many other places, especially locally.

So...a spice that needs a particular climate and soil composition. This island provides that.

Along with the diversity of other stuff they can and do grow, the mining, horse breeding and the exotic fruits (this, like the spice, will be a money-maker like you would not believe. A whole industry focused on drying and preserving these makes an awful lot of sense).

All you really need for the richness, is one or two unique products and a diversity of others. Saffron, AND/OR some kind of plant like woad, that isn't as common as woad and produces a unique color.

Wine is good because it's portable.

Part of your production problems are due to the population numbers you are starting with. Now it's true that in Rome's heyday before their fall, they did top over 1 million, but... See this link for charts on largest populations in Europe. If this is your model, a city of 300,000 would likely be if not the largest in the world, fairly close to that. A city of over 100,000 isn't that common either.

Paris didn't reach a population of 500,000 (or half million) until the 1600s. During the 16th century or 1500s, Paris was the largest city in Europe, with a population of about 350,000 in 1550. In 1400s, which is the century you're going for, Paris had about 280,000.

So a lot of your food supply issues will evaporate a bit when you calculate for the lower populations overall.

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    $\begingroup$ Thank you so much for this. I'm especially grateful for the population estimates - as I commented above I worded that part of my question really badly, but I'm definitely still highballing the overall population size so this is really helpful to me. Exotic fruit preserving and saffron are both fantastic ideas, thank you so much! Such a helpful answer. $\endgroup$
    – Elle
    Commented Mar 27, 2018 at 18:21
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    $\begingroup$ @Elle You'll notice population drops and populations holding steady from 1300-1400. This is because of the Black Plague. Outbreaks killed 30-60% of the pop. in some places. It took about 200 years for the population to recover to previous levels. If there was no Plague in your world, those higher numbers would make sense, so you can look at the 1600s as your model--even so, Constantinople is the highest there at 700,000. $\endgroup$ Commented Mar 28, 2018 at 3:54
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    $\begingroup$ @Elle But the flipside to no plague is that Renaissance might not have happened so quickly. The labor shortage created by the plague made workers realize their value and created a much more mobile population. The plague sort of woke up the lower class and began dismantling Feudalism in favor of Mercantilism. I can see the Renaissance happening without it but--it might have taken longer... $\endgroup$ Commented Mar 29, 2018 at 2:04

This island, considering its good climate, could feed its 50 thousand inhabitants, as well as some 50 thousands in the capital. But grain production would not bring too much riches, you will need more. You have already mentioned more profitable commodities, like wine. You may also add olive oil, linens, or put a silver mine in addition to the gold one.

But the most lucrative opportunity for your island seems to be the trade. If it lies on a popular trade route, its merchants are guaranteed to be rich. You may create a Venice-type city that controls the trade for most of the continent to the north. In that case, you don't need grain, wine or even gold - just good ports and fast ships.


If you want your island to supply 5% of this city's needs, we need to find out what those needs are. For a population of 1 million people: an average person needs ~2,200 calories per day, so ~ 803 billion calories per year. For simplicity, we can look at what 1 bushel of wheat can provide in calories. One one-pound wheat loaf provides 1,259 calories(https://www.fatsecret.com/calories-nutrition/usda/whole-wheat-bread?portionid=..), one bushel of grain produces 90 loafs per bushel(http://nationalfestivalofbreads.com/nutrition-education/wheat-facts). Thus, one bushel of wheat can provide ~113,310 calories. So, we need ~ 7.1 million bushels of wheat to feed your city. Therefore, an island would need to produce just over 350 thousand bushels of wheat annually to supply 5% of that city's needs plus another 350 thousand bushels for their own population for a total of 700 thousand bushels.

For farming methods, I found the Open-Field System as a popular farming method for the middle ages. To get an idea of what your island could produce, we should look at the typical method for land distribution and production. From the article https://en.wikipedia.org/wiki/Open-field_system:

The village of Elton, Cambridgeshire is representative of a medieval open-field manor in England. The manor, whose Lord was an abbot from a nearby monastery, had 13 "hides" of arable land of six virgates each. The acreage of a hide and virgate varied, but at Elton a hide was 144 acres (58 ha). A virgate was 24 acres (10 ha). Thus, the total of arable land amounted to 1,872 acres (758 ha). The abbot's demesne land consisted of three hides plus 16 acres (6.5 ha) of meadow and 3 acres (1 ha) of pasture. The remainder of the land was cultivated by 113 tenants who lived in a village on the manor. Counting spouses, children, and other dependents, plus landless people the total population resident in the manor village was probably 500 to 600.

For simplicity, we could round up the size of one village to ~2,000 acres of arable land with a population of 600 people. It later states in the article that. Now, how much did one acre of land produce. From the same article, it states:

Wheat and barley were the most important crops with roughly equal amounts planted on the average in England. Annual wheat production at Battle Abbey in Sussex in the late 14th century ranged from 2.26 to 5.22 seeds harvested for every seed planted, averaging 4.34 seeds harvested for every seed planted. Barley production averaged 4.01 and oats 2.87 seeds harvested for seeds planted. This translates into yields of seven to 17 bushels per acre harvested. Battle Abbey, however, may have been atypical, with better management and soils than typical of demesnes in open-field areas. Barley was used in making beer – consumed in large quantities – and mixed with other grains to produce bread that was a dietary staple for the poorer farmers. Wheat was often sold as a cash crop. Richer people ate bread made of wheat.

Because of the ideal climate, we will take the higher side of the production per acre of 15 bushels. Based on your proposed 7,000 Square kilometers of space, that would give you approximately 1,729,737 acres to work with. Not all of it is arable as there are two large central mountains, and other forests and such. So we will say that ~60% of the land is readily usable for planting: or 1,037,842 acres. Given that you want a population of ~50,000 on your island, you could have ~84 settlements (50,000/600 per settlement) of 2,000 acres a piece for a total needed space of 166 thousand acres which easily fits in your land budget. This land would produce 2.49 million bushels of wheat in a year. Which is 3.56 times your desired amount (30% of city needs, plus your island's needs).

All of this would give you tons of room on the island for things like fruits, vineyards (easily the most profitable item you could produce short of gold depending on the reason for demand, in the middle ages, it was the church that caused a demand for wine). Keep in mind, this family would likely have to be nobility to maintain control over such an area, but that's not in the bounds of the question.



There are many reasons why islands are not normally breadbaskets in real life, you could go around the size limitation by putting an old volcano on the island, some ancient eruption filled with rich red soil.

Alternatively, go for fishing. These islanders could be the best fishers around.

But island-nations are usually knwon as trading hubs, just think about the British Empire and how that one tiny island managed to conquer so much land.

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    $\begingroup$ I beg to differ. Most Caribbean Islands for example have been used as plantations mainly to provide agricultural products for Europe. $\endgroup$
    – Daniel
    Commented Mar 27, 2018 at 17:44
  • $\begingroup$ They weren't used to grow wheat or maize, but coffee, tobacco, and sugar cane. Those were specialty foods. $\endgroup$
    – Sasha
    Commented Mar 27, 2018 at 21:55

I would say it's totally possible to feed 5% of the capital's population...

During that period in France, 1km2 of crops could feed up to 100 persons (with the best crop yield).

So you would need at least 500 km2 of cropland to feed 50 000 persons. That means you can feed your own population with at least 7% of your island dedicated to cropland.

If you use 14% of your land to produce crops, you can feed your people and also 50 000 persons in mainland (5% of capital's population). With 21% of croplands, you can feed up to 100 000 persons abroad.

By the way I would add a few volcanoes on your island, to increase soil fertility.

  • $\begingroup$ Add to that, in the climate OP describes you would probably get more than one crop-cycle per year ... $\endgroup$
    – Daniel
    Commented Mar 27, 2018 at 17:47

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