I need to know how long it would take to conquer a continent the size of Africa.

  • Don't worry about food or materials, let's just assume that is taken care of.
  • Also, there are no huge cities with millions of people in them. think more like medieval towns with walls and a few thousand people.
  • In this world they still use armor and swords to fight.
  • most of the land is forests and plains.

The things I need to know would be.

  1. The size of army I would need and also factor in recruits from every town or village that join in to help the army.
  2. How far could an army move in a day.

Anything else I would need to know you can also throw in here because I guess writers block decided to hit me while I was typing this.

Edit: I want to know if it can be done in 10 or so years


closed as too broad by Aify, JDługosz, Brythan, Hohmannfan, DaaaahWhoosh Dec 11 '16 at 22:17

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ The second subquestion is answerable. The first is not. We don't know how many civilians are in the continent, nor how big their armies are, nor how fast you want to do it. A really huge army could split into parts and invade multiple areas at the same time. A smaller army could conquer areas sequentially. $\endgroup$ – Brythan Dec 11 '16 at 13:01

The answer is very much it depends. You state that food and materials are being taken care of, but even if you have huge silos of grain in some port town you still need to get it to the armies. Let's assume magic carpets do that.

  • You wrote that there might be recruits from captured villages. That sounds as if they would join, and not require occupation troops to keep them in line. Do you have a political/social/religious message that would get the population behind your project? If so, call it 50 to 100 years.
  • There are modern numbers from counterinsurgency theory which say you need about 20 troops for every 1,000 inhabitants for occupation. Finding that many troops without local recruits is going to be a challenge.
  • Depending on the terrain, an army can march 10 or 20 miles on a good day. If they do that several days in a row, they will need to rest and refit.
  • 20th century armies worried about taking ground and holding contiguous fronts. Medieval armies were a few hundred men, marching through the landscape to a field of battle or to besiege a castle. So getting a small, reliable band into the palace of the emperor (if there is such a palace) might decide everything, no need to take and hold each village.

Read the Anabasis by Xenophon, even if that is a couple of centuries early for your setting, or Bellum Civile by Caesar.

  • $\begingroup$ Let me recommend Sun Tsu's Art of War, a 6th century BC Chinese leadership manual. It has some good wisdom on strategy that can keep your army effective at its smallest possible size. $\endgroup$ – Columbia says Reinstate Monica Dec 11 '16 at 13:01
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    $\begingroup$ @RobertColumbia, I think the Art of War is too abstract for this. A small band walking from village to village in a vast country, that's more like it. $\endgroup$ – o.m. Dec 11 '16 at 13:27

I second o.m.'s answer: it very very very much "depends".

  • If that continent actually is Africa then a pre-modern state simply cannot conquer it completely because their armies cannot move through dense tropical forrests at all, because in large parts of Africa tse-tse flies would kill their horses, because Africa is divided into countless political structures which have to be conquered individually, because pre-modern states simply don't have enough people and transportation etc.

  • On the other hand, if that continent has favourable terrain and is already integrated in one political structure (or a handful of political structures) then it can be done relatively quickly by defeating the imperial armies in a few battles and taking over; for example Alexander the Great conquered the immense Persian Empire -- from Egypt to the Indus -- in 8 years (334-326 BCE), and the Mongols under Ögedei, Güyük, Möngke and finally Kublai Khan took over the entire Chinese empire in about 40 years (1234 to 1279).


Define "conquer". This question is like one asking how long a date should last, or how long a book should be. It is obvious that you will need to: 1. Have sufficient troops to defeat any military opposition and 2. Have sufficient troops to occupy/police/administer the land you have won. If you assume your 'reign' will be just as popular as the old one was, then your military/police support will need to be identical. That is a huge number of men/people - but it clearly depends on the pre-existing governmental structure. Generally, there will always be local people willing to support you, but you'll still need to train/indoctrinate them, as well as supervise them (i.e. your new government). You apparently envision a single army - and that's ridiculous. You're not going to conquer a continent going town to town with a single army. OTOH, if the continent is ruled by a single king/queen/emperor then all you need is to take over his/her position and surround yourself with enough supporters to overcome any opposition. 10 people might do it, 10 million might not be enough. Anything else you need to know? Sure is. Lots. Trump "conquered" North America in about ~18 months. It took Europeans ~300 years to conquer N.A. from the "natives". So, somewhere in between is reasonable, Africa is 23% bigger than N.A.


You can start with a classic historical example: Alexander the Great. During a 10 year period (335 to 325 BC) he conquered an empire of about 2 million square miles. Since the continent of Africa covers about 11.7 million square miles (call it 12 even), this suggests a conquest time of 60 years. This is going to be a problem, since Alexander was one of those extraordinary commanders who never lost a battle, and who inspired loyalty in part by fighting with his men. Swinging a sword in battle for a 70 or 80-year-old man is not entirely realistic. Furthermore, the odds of actually surviving 60 years of battles is pretty small - Alexander was seriously injured once.

This was done with an army which varied in size in the range of 30 to 50 thousand men, about half being mercenaries. Again, a 60 year campaign is going to be a problem as the original body of troops gets whittled down. Furthermore, Alexander was stopped in India by mutiny of his troops, who hadn't been home in 8 or more years, and asking any troops to sign up for lifetime exile is unlikely to get good results.

All this means that the conquest needs to be the result of policy in a large central government, rather than the result of one man's driving ambition. The government would need to ship out both replacement and occupation troops and administrators for the conquered territories, rather like Rome, and it would need to produce both good troops and competent (rather than political) commanders for 60 years. This is, on the face of the historical record, unlikely.

  • $\begingroup$ I should of added that the whole Southern point of this continent was in a civil war amongst tribes and towns. So they were weakened before he ever reached them. The commander of the army is inspired by Alexander the Great as he is was one my favorite historical people. $\endgroup$ – icefire Dec 11 '16 at 16:01
  • $\begingroup$ @icefire - "The commander" - what THE commander? A campaign of this duration will have multiple commanders - 60 years is far too long for a single. $\endgroup$ – WhatRoughBeast Dec 11 '16 at 16:45

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