The Hanseatic League was not so much a league of cities as it was a league of merchant associations within the cities of Northern Germany and the Baltic. Trade in the middle ages was a dangerous and risky business and the only way for merchants to protect themselves was by travelling together. This banding together of merchants on the road led to their alliances at home as well. In the case of the Hanseatic league the impetus for its formation was trade along the Kiel "salt road" which did not run between Kiel and Luebeck, but between Hamburg and Lubeck but was named after the town where the salt was mined.
The Hansa was founded in the twelfth century by an alliance between the northern towns of Hamburg and Luebeck which lay on opposite sides of the base of the Danish peninsula. Luebeck fishing boats had easy access to the herring spawning grounds off the coast of Scania (The lower tip of Sweden, which at that time was Danish territory). A large portion of the diet of Christian Europe was made of fish since there were many fast days and the church forbade the eating of meat on Friday. Luebeck was in a position to capitalize on a large commodities market in herring, but one thing held Luebeck back. With no refrigeration or canning the shipping of a highly perishable commodity like fish was problematic. Hamburg, on the other side of the Jutland peninsula, had easy access to the salt produced in the salt mines at Kiel, and salting and drying of meat and fish made transport and distribution possible. It was in the interest, then, for the merchants of these two towns to open trade along the "salt" road.
The trade between the merchant associations of Hamburg and Luebeck provided a model for the merchant associations of the other North German cities to follow. In 1201 Cologne, already wealthy, joined the league. Danzig, whose port was a gateway to the eastern Baltic also joined as did most of the important Baltic port cities. By the height of the Hansa's power merchants from over sixty cities had joined the association. While each city had its own merchant association the alliance formed a loose Diet, or parliament, to govern inter-city trade and common policies. In most respects the policy of the merchants was protectionist and aimed at producing a German monopoly in the markets they supplied.
The Hanseatic Diet met only infrequently and was filled with divisive politics based on differences in regional priorities. It was more frequent that the regional assemblies, known as "thirds", met. There was a Rhennish third based on the Rhine trade, a Wendish third based on Baltic shipping out of Luebeck, and a Prussian third based on the trade of grain from the lands of the Teutonic Order. The predominant town in all dealings was Luebeck, which held a central position at the Baltic side of the Danish Sound. Other member cities often complained that the merchants from Luebeck were given advantages over their own merchants.
While most of the cities in the Hansa were within the domains of local feudal lords and the citizens of these cities were feudal vassals Luebeck was one of the few "free cities" or more properly, it was an imperial city which owed its allegiance to the emperor alone. This in itself gave Luebeck an advantage over many of the other cities. When added to that are the position it held geographically and the access it had to the rich herring fisheries its predominant position in the alliance is understandable. Almost all trade to the Baltic, either coming or going, went through the port of Luebeck.
The cargos in the port of Luebeck consisted of salt, herring, grain, timber, honey, amber, ships stores, and other bulk commodities. These were not cargos that made quick fortunes, but they were a steady trade, and the Hansa held a monopoly on a great deal of it, if not all. This was accomplished not only by the formation of the trade association, but also because the Hansa had produced a new and innovative ship design, the Baltic cog
Before the development of the cog ships in the north of europe were built in the same design as the viking ships of old. These ships were strong and seaworthy, but could handle only limited amounts of cargo. The average scandinavian design cargo ship of the period held about 20 lasts (a last being a measure of volume not of displacement, but being roughly equal to two metric tons). A Baltic cog, on the other hand, ranged from 50 to 200 lasts with an average size of 100 lasts. It was clinker built of abundant Baltic timber from the forests of Novgarod, with a flat bottom and a center mounted rudder (which was a technological advance for the period). The ship could be fitted with a removable keel and held one mast with a square rigged sail. With their flat bottoms they were well fitted for sailing in shallow waters, a design factor still used by small sailing ships in the Netherlands. They were rugged, held a lot of cargo, and sailed like barges compared to the sleek viking design. They also had the disadvantage, because of their square rigged sail, of not being able to sail into the wind. It is lucky, therefore, that in the Baltic and North Sea the winds blow with a seasonal change of directions.
Sailing in the middle ages was not very technologically advanced and aside from the crude compass and Jacob's ladder, or perhaps and astrolabe, there were no navigational tools. Because of this most sailing was done in view of the coastline following the guide in the Book of the Sea. This book gave directions based on the silhouette of the headlands and soundings of the depth. If you sailed west until you reached a point where you could see a particular church spire and your depth was so-and-so fathoms, then you should turn north northwest and sail for two days until the depth reached so-and-so fathoms and you would shortly find this or that particular landmark by sailing west. Such was the method of navigation in most of the middle ages. If you put in at night and sighted the pole star with the Jacob's ladder or astrolabe you could find your latitude. You could also try sighting the sun at midday, but it would make you go blind and you were probably sailing then, making sightings impossible because of the rolling of the sea. As far as longitude, there was no way to calculate it, you simply had to rely on landmarks. Aside from the difficulty of navigation the danger of piracy was very real.
Because of the dangers involved with shipping cargos, especially since there was no such thing as insurance, the common practice was to form partnerships and have each merchant buy a share of a cargo or a share of a ship. By spreading your investment over several cargos and shipping them on several ships the risk of a catastrophic loss was reduced. The same is true of investing in shares of several ships, if one was sunk or taken by pirates, the others may come through with their cargos intact. The sailors who manned the ships often worked for a share of the profits from the voyage and the captain was often one of the shareholders of the ship. Ships rarely sailed alone but usually joined into large convoys for mutual protection. The convoys would sail following the seasonal winds and make the circuit in a year's time.
On land the base of operations for a merchant was his "factory". This should not be mistaken for the manufacturing plant it now represents, but was usually a three storied structure containing on the lowest floor the retail outlet where buying and selling took place, on the second floor a warehouse, and on the topmost floor offices and living quarters. Abroad the Hansa had foreign "counters". These "counters" were basically trading posts, though the most important were more elaborate and may have been whole neighborhoods. The five major foreign "counters" were the "counter" in Wisby on the island of Gotland, the "counter" in Novgarod, the Norwegian "counter" in Bergen, the "counter" at Bruges, and the English "counter" in London. In order to be eligible to work at one of the foreign counters a merchant had to be a married man of good reputation and make a commitment to serve there for a full year (since the sailings of the convoys were annual). It was an attack against the "counter" at Wisby that formented the wars between the Hansa and the Danish crown.
Waldemar Atterdag, King of Denmark, was envious of the wealth the Hansa was taking from the herring fisheries off the coast of Scania. Waldemar felt, perhaps rightly so, that the revenues from the fisheries in his territories should be more under his control and did his best to reduce the privileges his predecessors had given to the Germans. In 1361, just after the counsellors from the Hansa had returned to Luebeck after re-negotiating the rights to the herring fisheries, news came that Waldemar had sacked the city of Wisby on the island of Gotland. The leaders of the Hansa in Luebeck, who had the greatest interest in the Wisby "counter", were outraged and pushed for war. The Wendish third was in favor of the war, but the Rhennish third saw no interest to be gained from it and the Prussian third were forbidden to take part by the Grand Master of the Teutonic Order, who was a friend of Waldemar's, though they were allowed to give financial support. Despite the lack of support from the other thirds the Wendish third decided to undertake a campaign against the Danes, who they saw as pirates. They picked Johann Wittenborg of Luebeck to lead the expedition and fitted out 52 cogs, each with 100 men-at-arms, and 104 smaller auxiliary vessels to carry out the attack.
The campaign was initially quite successful and the fleet sacked Copenhagen and took with them the bell from the main church. They then went to attack the Danish fortresses on the Scania coastline of the sound. The plan was to meet with an army provided by Magnus Erikson, King of Sweden, who held sovereignty over Gotland in order to besiege the fortress of Halsingborg. When the Hansa fleet arrived there was no Swedish army to be found and Johann Wittenborg made a grave error in taking the men-at-arms off the ships in order to besiege the fortress. Several days later, with the soldiers all on land, the Danish fleet sailed into view, and with only skeleton crews on most of the German vessels most of the German ships and Provisions were either sunk or taken captive. Johann Wittenborg was forced to sue for peace and march home in disgrace. While the merchants in the Hansa tried to save his life the outraged citizenry of Luebeck demanded his death and a year after sailing he was publicly beheaded in the city square. The Hansa, in the terms of peace, was forced to cede most of its revenues from the herring fisheries to the Danish crown.
Waldemar was a cunning man and he felt that since only the Wendish cities had taken part in the war with him he had only made peace with the Wendish cities and not the Prussian ones. Therefore, Danish attacks against the Prussians increased through the next decade causing the Prussians to repeatedly call for a reopening of the hostilities, but the Wendish cities, who had lost so much in the first war without the support of the Prussians and the Rhennish third, were not in any hurry to take the risk again. Finally the situation became totally intolerable and the Wendish cities were persuaded to join into a unified campaign which would include all of the cities. This time the Grand Master of the Teutonic Order, who had lost revenues to Danish attacks, did not interfere with the Prussian cities' involvement. Further Waldemar, who had taken the last half decade to try to consolidate his power against his own nobles, found his nobles either unwilling to support him or in alliance with the Germans. Waldemar was forced to flee Copenhagen and stay as a guest of the Grand Master of the Teutonic Order, who treated him graciously as a guest but gave him no aid against the Hansa, counselling him to sue for peace instead. Waldemar had no choice and agreed to a treaty which gave the Hanseatic merchants sweeping rights.
The Germans gained control over the revenues from the herring fisheries, control over the fortresses of the sound, the right to be the only ships allowed to enter the port of Bergen with their tops in place (Haakan Haakanson, the Norwegian King, had allied with Waldemar), and the right to veto any person's ascension to the Danish throne for fifteen years. When that time period was done the Hansa returned the fortresses to Danish control, though popular sentiment was against it. Unfortunately the Hansa was in a period leading to decline. The privateers that were given letters of marque and reprisal in the war liked their jobs too well and many remained as pirates working out of the area around Gotland. In addition, the herring spawning ground suddenly and unexpectedly moved to the North Sea where the Dutch ships could move into the market. Also the English with their Round Ships and the new Carracks and Caravels began to take over the shipping the Germans had previously monopolized in the North Sea. By the end of the fifteenth century the power of the Hansa was a mere shadow of its former days.