What Were the Types of Sieges?

Question

As I understand it, there were two types of sieges. One was where the attacking army would "camp," surrounding the city, and let the defenders run out of food. An example was Ulysses S. Grant's siege of Vicksburg.

The other kind was where the attacking army would try to invade the city by breaching the walls, scaling them, or by tunneling under them (e.g. Grant's forces at St. Petersburg, Virginia, or Santa Anna at the Alamo).

What considerations would cause an attacking army to choose one kind of siege over the other?

Was one easier to defend against than the other?

Answer 1

I don't believe there is a separate name for either type of siege, they are both considered simply a siege. The whole point of a siege in general is to overtake the castle, and as you indicated, there are different means for going about doing this.

The considerations for choosing one over the other ultimately comes down to a basic function of time and resources. If you have plenty of resources (food, supplies, etc.) and are willing to wait them out, then a siege of starvation might be a viable option. This would ultimately resort in the lowest loss of life. The strategy is to simply outlast the defenders, who will have no way of replenishing their supplies because the attackers would have cut them off. The disadvantage of this is that it meant that you had to tie up a considerable number of men to keep the castle under siege. In the middle ages, a good portion of your army would have been peasants, and they were very likely to get bored and frustrated and longing for home, so this would be a risky tactic. In addition to that, it would become quite costly to keep paying for the supplies to provide for these troops, and before long the cost would become unreasonable.

The alternative, therefore, was to attack the castle by any means available to try to get it to fall. This would usually consist of a concentrated assault on one particular wall in an effort to either weaken the defenses there or overun them. The ultimate objective would be to breach the castle and either force the occupanst to surrender or simply kill them and be done with it. This option was much more common because it was more expedient.

Since each involves dramatically different conditions, its hard to say one would be easier to defend against than the other. The first option I listed would likely resort in a lower loss of life, so it might be preferred from a defensive position. As far as defending against an all out attack, it would really depend on what kind of castle you have and what resources you have within it. Some castles would be easy to defend because they were built to last, while others were mostly built for show, and therefore not easily defended.

Answer 2

In the 17th and 18th centuries, fortresses had changed from the medieval castle, and were designed for artillery and musket defense. A methodical siege technique evolved, primarily associated nowadays with Vauban. This involved digging saps and parallels, and setting up artillery positions in the parallels. Typically, the third parallel (trench roughly parallel to the fortress side), supported by saps (communicating trenches of a particular design), would try for a breach in the walls and an assault.

There were other techniques available. There was the blockade, an attempt to starve the defenders out. There was the escalade, in which the attackers rush forward with ladders, presumably at night, and hope not to be blown away by grapeshot and musket balls before they could scale the walls. There were attempts to enter the fortress by other means, such as a heavily loaded wagon that would have its wheels knocked off while blocking the gates.

Answer 3

Attacking a fortification is a risky proposition indeed and many soldier will die trying. So, softening the defenders could be done if you had the manpower to starve them out. The longer the siege, the more there was a chance of both sides would develop disease and one will have to either surrender or leave. Sieges were, generally, not a good idea as they would tie down the attacking army in one place, leaving the rest of the enemy forces a chance to regroup and continue the fight.

As to which was easier to use and which was easier to defend against, it all boils down to good generals.

Generals used both approaches, mostly whichever would give them the quickest victory -- no country has profited from prolonged warfare. Hannibal never could have siege Rome because he did not have the manpower and fleet he would have needed to force the city to surrender and he had no hope to storm it. Scipio at Carthagena used the storm the walls because he had to. Caesar used the wait at Alesia because he had to. Béziers was taken because of a blunder by the defenders. Constantinople fell because canon could be used to smash the city walls. Vauban created new fortifications that took gunpowder into considerations. The ligne Maginot was unbreakable but could easily be circumvented.