How does a medieval european (1200, let's say) army operate? [closed]

Question

Let's suppose medieval army A is preparing to attack medieval army B. Both armies are out on the field.

Q1: How close can they realistically be? Can one army see the other? If they were to charge against each other, how long would would it take from the attack order until the moment swords clash?

Q2: What is life like on both camps? What do soldiers do while they're not in combat?

Q3: Is it believable that those armies fight more than once (They have a round of combat, retreat and sometime later resume fighting)? How many time would pass between rounds?

Q4: When and for how long do they fight? If night falls, both of them retreat? Or do they keep fighting?

Q5: At any given time during a fight, are ALL of the soldiers fighting? Or some of them remain on camp as a backup?

Q6: How big can the armies reasonably be?

While answering, keep in mind that food is not an issue. Both armies have reliable supply lines.

If you want some more context, assume this is around 1200. Cavalry is an important factor in warfare, but foot soldiers are also relevant. There are no gunpowder weapons. The bow is still the most widely used ranged weapon.

Answer 1

As usual for such questions, let's assume that by "medieval army" you mean specifically an army typical of the Western European High Middle Ages, even more specifically an English, French or Imperial army of the 13th to the 15th century. (I don't know why most people just forget that the Middle Age period one thousand years long and covers vastly different cultures. And that's the European Middle Age period.)

Let's take a famous medieval battle: the battle of Agincourt, which took place in 1415 (at the very end of the Middle Ages). There is a detailed article on Wikipedia, and, even better, there is an entire book, The History of the Battle of Agincourt by Nicholas Harris, London, 1832, available from Archive.org in multiple formats.

Basically:

1. How close can they realistically be? Can one army see the other? If they were to charge against each other, how long would would it take from the attack order until the moment swords clash?

   They would certainly see each other: in the Middle Ages they didn't have over-the-horizon radar and indirect artillery fire. If they cannot see each other there is no way to find each other in order to do battle.

   A cavalry horse covers 340 to 400 meters per minute at a gallop. (This is about half the top speed of a race horse.) The armies will most likely be separated by about one third to one half a mile at the start of the battle; when one of the sides charges they move at a trot to about 100-150 meters and then they go to a gallop. How much time will pass between the start of the battle and the first clash depends on the specific tactics.

   Swords clash: not likely. The most usual use of a sword on a medieval battle field was for an officer to brandish it crying Forward! After me! Swords were by and large decorative side arms for rich people. Lances clash with the shields, pikes clash with the horses, shields clash against shields...

2. What is life like on both camps? What do soldiers do while they're not in combat?

   They stand guard, forage, train, eat, wash, mend their equipment, dig latrines, sleep, gamble...

3. Is it believable that those armies fight more than once (They have a round of combat, retreat and sometime later resume fighting)? How many time would pass between rounds?

   It depends what you mean by "those armies". Those kings, yes, possibly. Those exact armies, no, not likely. One side wins and one side loses, or one side decides to disengage (a tactical loss) in order to gain a better position elsewhere. Battles are not sporting events, they have a purpose subordinated to the strategic goals. What may happen is that the battle continues over several days; in this case, at night everybody just stays put with minimal combat.

4. When and for how long do they fight? If night falls, both of them retreat? Or do they keep fighting?

   See point 3. They most certainly don't fight at night -- it's the Middle Ages, no way to see in the dark. It may well be the case that both sides stay put and wait for daylight, or one or both sides may decide to disengage, or (less likely) to maneuver (medieval armies were not really able to maneuver tactically).

5. At any given time during a fight, are ALL of the soldiers fighting? Or some of them remain on camp as a backup?

   It's not likely that all the soldiers are fighting, unless (a) the commander has seen a tactical opportunity and has committed all the reserves, or (b) the situation is desperate. A wise commander will keep a force as a reserve, to enable him to exploit any tactical opening. But they won't remain "in camp". They will be on or near the battle field, at the ready.

6. How big can the armies reasonably be?

   Look up the Hundred Years' War on Wikipedia; there is a list of battles, and for each battle you will find a nice table summarizing it. Basically, 5000 men is a sizeable army, 10000 men is a large army, 25000 is a huge army the likes of which the world had never seen before. (The logistics prevailing in the Middle Ages were such that feeding 25000 men for more than a few days was a superhuman feat.)

Note that armies very much prefer not to fight other armies. Usually, a set piece battle takes place either because one side has outmaneuvered the other so that they cannot continue their campaign unless they go through the opposing army, or because both sides stumbled into each other by chance. (In the case of the battle of Agincourt, the first case happended; the defending French outmaneuvered the English, putting them in a position where they had to go through the much larger French army if they wanted to avoid death by starvation.) If at all possible, the commander of the attacking side will try to go around the defending army, and the commander of the defending side will try to occupy a strong defensive position where the enemy would be strongly incentivised to refuse to attack.

This being the Middle Ages, it is possible for two armies to do battle although any commander in the Antiquity or the Modern Age would have preferred to avoid it; they were not fully rational in the Middle Ages, and they did have to operate with very limited tactical flexibility, given the generally poor training of the soldiers. Even the knights had poor military training -- they were well trained in fighting as individuals, but had only minimal notions of fighting in formation, obeying orders, maintaining unit cohesion and so on.

Answer 2

Much depends on how well the polity is organized and run.

Henry V raised and equipped a very efficient army for the campaign which culminated in the battle of Agincourt, there are literally hundreds of records of contracts, bills of sale and other administrative paperwork which allowed Henry to raise a large force of yeoman archers, infantry, knights and artillery as well as the multitude of skilled craftsmen to build and maintain equipment and hire a fleet of ships to bring the assembled forces to Harfleur, besiege and take the town, then march through the countryside on a chevauchée to Calais.

On the other side of the channel, the French were busy fighting each other, and Henry counted on the disorganization and inefficient administration of the French to hamper their ability to raise a force against him (much like the French had not been able to mount an effective defence against the English in previous campaigns). This was actually true to a large extent, and only a groundswell of proto nationalistic feeling really allowed the French to gather so many knights own one place to fight Henry at Agincourt. Had things gone a bit differently, this large force might never have come together, drifted away as Henry managed to avoid them (or was delayed in the march) or even fought each other.

So like the old saying goes, amateurs study tactics, professionals study logistics. In the Middle Ages, very few polities had the sort of professional organizations needed to raise or support armies in the field. The very idea of a standing army (like the Roman Legions) and essentially been lost, so for the most part you are talking about ad hoc organizations of fighters rather than military organizations the way we understand them.

Answer 3

As the comments pointed out, there is no generic medieval army. My answer concentrates on the HRE.

• Q6: Armies would be small. Hundreds of knights, hundreds of mounted followers, thousands of foot infantry (badly trained, badly armed), thousands of camp followers (who would not fight in battle, but perhaps in self-defense). Obviously an army of English yeomen archers or Swiss infantry would look different ...
• Q2: Vassals would be called up by their feudal overlords, bringing their own vassals in turn. That also dictates the "org chart" of the army. It also means the troops are only assembled for the battle or campaign. They want to go back to their fields and prepare the next harvest.
• Q5: Knights had a real problem with being held in reserve. It is dishonorable if they do not fight while their peers do. So it takes either a strong-willed leader or commoner troops.
• Q1: It was possible that the battle is almost pre-arranged. Heralds on both sides would talk to each other. Of course both sides would try to get good positions, but maneuvering an army in battle formation was almost impossible.

Answer 4

Food is always an issue. It is believed that the reason Mongols conquered more territories than romans ever did was because of a prolonged period of excessive harvests in Asian countries. In 1227 their nominal army size was 129,000 people. Only heavy fortifications and help from other countries could help against them. They easily won battles on open grounds and burned whole cities before help arrived.

Before the era of gunpowder, if you defend, it was easier to sit behind the walls, what romans actually did a lot. In early middle ages wars were won by just sitting in a well defended castle. To take a castle one needs at least 4 times more men. So why fight on the field if math was not on your side?