"War is nothing more than a continuation of politics with other means."
(Carl von Clausewitz)
War is as old as the human race itself and has been conducted since the beginning of time; about land, women, livestock, or just simple survival.
When the early humans learned how to make weapons for hunting purposes they quickly found out that those weapons could also be used to force their will upon others, take what they wanted, or defend themselves against other agressors, this knowledge quickly caused the first wars; the men of village 1 attacked village 2 to steal their goods, cattle, and women, the men of village 2 attacked village 1 out of revenge and burned it to the ground, the survivors of village 1 left their destroyed village and went to a fertile valley nearby where they attacked the native inhabitants to take the land for themselves, etc; war often has a domino effect, it leads like a red line through human history and most changes in human culture, religion, language and technology have been caused by wars, whether those changes were positive or not.
Not long after the first battles humans began to use war tactics, they understood that battles were easier when you attacked the right target at the right place and time, for instance; if village 1 has 10 young men and they want to attack the people of village 2 who have 20 young men they don't have much chance against an army that is two times bigger right? but what would happen if they would attack village 2 when half of their men have gone hunting? that way they can first attack the 10 men who are left, and if they win they can attack the other 10 when they return, combine this with the element of surprise and you stand a much better chance.
This clearly demonstrates human inventivity; they can use their intelligence to gain the upper hand while most other animals can only resort to their physical strenght.
Over the years tactical and strategical warfare was improved, something that will always continue and can also be seen in our modern times; country 1 invents a new type of rocket that can be used to attack country 2 on the other side of the globe, country 2 feels threatened and invents a rocket that can intercept the rockets of country 1, country 1 equips their new rocket with a defensive system that disrupts the internal computer of the interceptor rockets of country 2, country 2 developes a new system to counter that, etc.
Other tactics can be remarkably simple;
Alexander the Great could not beat the Persian fleet so he simply conquered all the cities with ports along the coast which cut off the Persian fleet from their supplies, severely weakening it.
During the French-English wars the English gained a remarkable victory at Agincourt by luring the French knights into a swampy area where their horses could not manouver well.
During WW2 soldiers buried mines and made car tracks over them with rubber tires, the enemy thought that an area where cars could cross would be clear of mines and entered it.
When the nazi's invaded the Netherlands in WW2 the Dutch destroyed some important dikes which flooded the hinterlaying terrein, this prevented the enemy to use their tanks, the nazi's responded by using paratroopers but the delay allowed the Dutch army to evacuate the queen and many of their soldiers to England from where the war could be continued, during the war with the French in 1794 the same trick was used but because of the cold winter the water froze and the French army could cross by using ice skates.
During the Gulf war in 2003 the Iraqi's had dug oil pits around Baghdad that they set on fire so that the smoke disrupted the thermal vision systems of American airplanes which made it more difficult for them to bomb the city.
Other examples of war tactics are the use of maps, predefined routes to encircle the enemy, limiting enemy mobility by destroying their infrastructure, demoralizing enemy soldiers and civilians, propaganda, and other dirty tricks.
But I'm drifting off now, I shall begin with describing the war tactics that were used by Germanic armies.
Germanic warriors always tried to engage in hand-to-hand combat because they were superior in this tactic; Germans were extremely tall compared to the small Romans for example, this advantage allowed them to gain the upper hand in close combat, Germanic warriors were known for their bravery, ferocity, and physical stature, and most Roman soldiers feared them the most of all.
Most Roman victories over the Germans were gained by their higher level of organisation, the Romans were a united people with a professional army while the Germans were fierce warriors but hopelessly divided which prevented them from launching any coordinated attacks.
In later periods the Roman army recruited many Germanic men because of their quality in battle, some legions even consisted almost entirely of Germanic soldiers like Legio X Gemina that mostly consisted of Batavians and Cananefatians who were recruited in what is now the Netherlands.
Heerfahrt: the Heerfahrt was not really a tactic but more of a system, the word "Heerfahrt" (German) or "Heervaart" (Dutch) literally means "Army-faring" and it was the Germanic version of our modern conscription and mobilization.
In Germanic society the activation of the heerfahrt was decided by the þing, though in the Middle Ages this was done by the landlord, taking part in the heerfahrt was an obligation and a person who refused was considered a coward and sometimes even a traitor; refusing to fight for the freedom of your people was unthinkable and often punished with death.
During times of war every young man who was able to use a weapon had a "Heerpflicht" (German) or "Heirplicht" (Dutch), which means "Army-duty" and had to join the army, the age on which they had to do this varied; this could be 16, 18, but also 12, this depended on how much men were needed; the bigger the army had to be, the lower the age.
Calling in boys below 16 for conscription is nowadays unthinkable in most countries but in that time is was very normal, one must not forget that these times were much harder and that people became adult at a much lower age, parents already learned their children to handle weapons when they were very young so that they were able to defend themselves agains the hard outside world when they grew up.
The Scandinavians also had a rule concerning horses; during the heerfahrt they had to be given to the army when they were 2 years or older, most of the times the owner was allowed to use it himself in the battle, after the war the horses were brought back to their owners again.
Every person who was going on heerfahrt had to bring his own weapons and equipment, which was no problem since most Germans had at least one weapon at home because they believed it was their duty and their right to protect their family, a custom that still exists today in many American states.
Because most people were poor farmers they only had a shield with a spear or an axe, expensive equipment like swords, helmets, and chainmail was only used by nobles and professional warriors, though in later times the equipment of the common man became better too.
Sometimes there was a special stock of weapons that was divided among the warriors, but most of the times a person who wanted a better weapon either had to make it himself, buy/trade one, or capture it during a battle.
The warband tactic: the Germans used many different styles of fighting, the most common one was the "warband" tactic; they just formed a big army of warriors and attacked the enemy, relying on the individual superiority of their warriors.
This tactic was used by many ancient peoples like the Celts and the Dacians, the only difference was that the Germans used a much denser formation that was more difficult to break, another difference was that the Germans improvised and adapted themselves to the situation while the Celts often fled in panic when their lines were broken or their plan did not meet initial success.
The warband tactic was very popular because of the individual advantage Germanic warriors had over most peoples, they also tried to exploit this feature by screaming, hurling insults, and showing off; this frightened most enemies who were not used to this kind of intimidation.
The cavalry tactic: Germans did not often use cavalry and their warriors mainly fought on foot, however, some tribes were known for their use of cavalry and many peoples praised the good quality of Germanic cavalry, especially that of the Goths.
The horses that were used by our ancestors were not of exceptional quality but they were small, strong and robust, possibly tarpans.
In most cases horses were not trained to engage in different formations, despite this, Germanic horsemen could manouver very well and operated as a unit rather than as an unorganized band.
The Suebians trained their horses to hold their position when the rider abandoned them, this allowed the warrior to jump off his horse to fight with the enemy and then quickly jump on again without having to chase after his horse to get it back.
In the 1st century Germanic horsemen did not use stirrups because these were unknown in Europe in that period, saddles were already known but were not used much, Caesar even mentions that the Suebians considered the use of a saddle to be a sign of weakness.
Just like the later Medieval knights the Germanic cavalry mainly consisted of nobles, they were mostly armed with a shield and spear and were supported by light infantry; this light cavalry combined with light infantry allowed some speedy tactics; the cavalry could break through the enemy lines while the infantry could quickly follow to finish off the remaining enemy soldiers, a tactic that is nowadays called "blitzkrieg".
Some tribes were exceptionally known for using this tactic like the Goths and the Tencterians, Germanic cavalry was superior to the Celtic one which was proven during the invasion of Gaul, Julius Caesar was so impressed with them that he even used Germanic cavalry in his Roman army.
However, the strength of a Germanic army mostly lied in its infantry and the cavalry was mainly used in a supportive role or to break enemy lines.
Tacitus mentions that for this purpose the best warriors were chosen from the main army and were placed amongst the cavalry as some sort of stormtroopers, these elite warriors were called "The Hundred", because the best hundred men were chosen from the warriors of every district (gau) for this unit.
As soon as the cavalry charged the Hundred ran after them to support them in the fighting, this was a rather dangerous job so only the best warriors were picked for this.
Julius Caesar mentions a similar tactic in his work "Commentarii de bello Gallico"; after the horseriders of both armies had skirmished a little his Germanic enemies employed a special force of 12000 men; 6000 horsemen and 6000 footmen, each horseman chose a footman as his bodyguard and this person would then run along with him when he charged en protected him when he was wounded.
The stealth tactic: Germanic armies only tried to engage in battles they could win, the ones they could not win had to be avoided, or fought in another way.
The Germans were known for their strategems and tricks, a tactic we would now call "guerilla warfare", they used the speed of their lightly armed warriors to outmanouver the enemy and attack them in the back, they were also known for their effective ambushes and dirty tricks; they often promised the Romans their loyalty and when the Romans had turned their backs they organized an uprising and reconquered their lands.
Another trick was fighting in difficult terrain, Germania was covered with swamps and dark forests in which only the Germans knew the way, invading Roman legions got hopelessly lost in this "jungle" and desperately tried to stay out of forests and other places where Germanic warriors could ambush them, the Germans could easily manouver in forests because of their light equipment and their biggest victories over the Romans were gained in forests like the Teutoburger Wald for example.
Stealth tactics often saved the Germans from Roman occupation and it would not be exaggerated to say that Germania was to Rome what Vietnam was to the USA and Afghanistan to the USSR.
Battle formations: battle formations were also used, especially in later periods against the more advanced enemies, one of the tactics used was the Wedge, of which the Germans believed that it was invented by the high god Wodan who learned it to a human hero.
The Wedge, also known as "Swinehead", was a tactic in which warriors formed a triangle; the strongest warriors were placed at the tip while the rest were positioned at the flanks, when the wedge advanced it could break an enemy line and allowed the rest of the army to slip through, it was not considered cowardice if the wedge gave ground as long as it would retake that ground later in the battle.
A good defensive tactic that the Germans often used was the "Shieldwall" or "Wall of shields", a tactic that was similar to the Greek phalanx; the warriors formed a tight formation with their shields held in front of them to block the enemy assault while their spears were held forward to impale incoming soldiers and horsemen, the round shields overlapped eachother which gave an even greater strength to the wall because the shields reinforced eachother and an attacker had to push against the strength of 3 men instead of 1, the wall of shields was also a relatively easy tactic to use because the basic equipment of a Germanic warrior mainly consisted of a shield and a spear, it was imperative that all warriors cooperated to keep the line intact because if one person broke his rank he did not only expose his comrades to his left and right side to enemy attacks but he also endangered the rest of the army because one gap in the line was enough to allow the enemy to break through and defeat the entire army.
In his book about the campaign in Gaul Julius Caesar tells about a battle where the army of the Germanic king Ariovistus immediately charged towards the Romans at the beginning of the battle to prevent them from throwing their pila (throwing spears) at them, so the Romans drew their swords for close combat and Ariovistus' men responded by forming a shield wall in close formation.
Other tactics that were used was splitting up in two and attacking the enemy in both flanks like the "cowhorn" tactic the Zulu's used to defeat the English at Isandlwana, another dirty trick was presenting 1/3 of the army at the battlefield and keep the other 2/3 "hidden" behind a hill or in a forest or something, the enemy then attacked with less troops than they should and at the last moment the hidden soldiers came in and slaughtered the surprised enemy.
Of course there were numerous formations like this so it would cost too much time to write them all down, the Germans were inventive warriors and often adapted themselves to the situation so the tactic and formation they used often depended on the situation.
The retreating tactic: a typical Germanic tactic was the "retreating tactic", this was one of the most used tactics and many enemies fell for it; during a battle the warriors suddenly broke ranks and pretended to flee in panic, many enemies then believed they had won the battle and pursued the fleeing warriors to finish them off but after a long pursuit the Germans suddenly stopped, turned around, and reformed their ranks, at this point the enemy was often broken into a big, cheerful, pursuing mob that was hopelessly scattered over the battlefield, the Germans then charged back and finished off the surprised enemy.
Germanic warriors used this tactic throughout history and in the early Middle Ages the Vikings still used the tactic with much success.
The hit and run tactic: this tactic can be compared to the stealth tactic, an army quickly attacked a target and disappeared before countermeasures could be taken, this tactic was very helpful against strong opponents.
A variation of this tactic was used by the Vikings; they used ships to attack and plunter a village or monastery and left before reinforcements arrived, in earlier times the western Germans used this tactic very effectively against the Romans who were helpless against this type of attacks.
During the Great Migrations the tribe of the Vandals loaded horses on their ships which allowed them to penetrate deeply into enemy territory after the landing and also a quick way of retreating before the enemy arrived.