The Thirty Years War opened many avenues for trade and certain nations fighting in the war needed international trade to maintain their prosperity. Statistics for international trade during the Thirty Years War are difficult to acquire and regional variations took place throughout Europe.
Certain regional variations are known about.
We know that trade between Seville and Spanish America declined and that from 1600 to 1660, a general depression regarding the import of American silver took place.
However, during the same time, there was an increase in Atlantic trade by both England and the Dutch. At this time both nations had powerful and expanding navies to defend their merchant trade. We also know that sugar production in Brazil doubled between 1620 and 1650 and this would only have happened if they were finding a market for this produce. If Spain was not trading in sugar, someone else had to be.
The Baltic had been a valuable trading zone for many years. All ships had to pay a toll to get through the Sound to the lucrative Hanseatic ports. All ships had to pay a toll to leave the Baltic as well. These tolls were all registered and recorded and an examination of them gives a good idea of the state of the economy in the Baltic during the Thirty Years War.
After 1619, there was a significant fall in the number of ships that passed through the Sound. This would seem to indicate that the amount of trade was declining. However, this was also a time of increased ships tonnage and the toll records do not state how big the ships were at the time they passed through the Sound. One 500 ton ship could transport more than four 100 ton ships yet the toll records would only indicate that one ship had passed through the Sound at a particular time. The use of the Sound fluctuated throughout the war and dipped markedly only when war appeared to be directly affecting the region.
In 1630, when Gustavus Adolphus invaded Pomerania, it is almost certain that trade dipped during the initial stages of invasion for fear that ships could get caught up in the fighting. But once the invasion turned in favour of Gustavus, his army would have needed supplying and this would have been a good incentive for the owners of merchant fleets to involve themselves in trade in the region.
The German merchant fleets did not expand as much as the Dutch and English fleets. However, the ships they had were used by the Spanish and Italians to do trade in the Baltic. This, in itself, brought trading revenue into Germany. Though the figures for trade between Germany and the Baltic during the war look poor when compared to the latter C16th, the latter C16th was a good time for Baltic trade and make the figures for 1618 -1648 look poor when, in fact, they may have been simply average. During the war, Germany actually diversified her trade to metals, ship-building materials and linen. A stagnant trading economy is one that does not change to meet market changes. That Germany did change is at least an indication that her attitude to trading was sound and modern in its approach. In return for her new types of exports, Germany imported spices, wine, oil and fruits.
The Thirty Years War inevitably brought in a degree of economic protectionism. Wars usually contract the number of markets available to trade with and states have to adopt a more aggressive trading policy if they are to survive and to break in to the limited number of markets that are left. After 1620, England and the Dutch found new markets abroad in the New World and in the East to compensate for lost European markets.
Spain was struggling for her economic survival after 1621. The Dutch, in particular, were putting a great deal of pressure on her overseas trading posts. Within Spain, it was felt that the situation with the Dutch could only be resolved by war even if this would further compromise Spain's weak economic state.
Between 1621 and 1623, three new armadas were established in Flanders, Galicia and Gibraltar to support those in Cadiz and Lisbon. Their sole function was to harass Dutch naval and merchant ships in the Atlantic. In response to this, the Dutch had to increase the protection it gave to its merchant fleets. Clashes between the two were inevitable and the resultant loss of ships pushed up the price of insurance and lead to higher freight charges. The end result of this was a general rise in the price of the commodities being transported.
The Spanish did their bets to modernise their trading position during the Thirty Years War. In October 1624, the Almirantazo de Los Paises Septentrionales (Inspectorate for Commerce) was established to deal with trade between Andalusia and North Europe. It was based in Seville and was highly effective. Other Inspectorates were based in the Baltic and Flanders and their task was to win back trade from the Dutch. However, the Inspectorates had no brief to modernise the workings of Spanish and Portugese ports. Ironically, it was these ports on the Spanish mainland that needed reform if Spain was to benefit.
From 1625, Spain imposed a total river blockade in Northern Europe. This was a very effective move. Diary markets in Holland fell dramatically. The blockade was partially lifted in 1629 when it started to affect Flemish trade and its impact suitably weakened. By the mid-1630's, the Spanish had been driven out of many coastal areas in and around Holland and the impact of the blockade fell away.
Predicting trade patterns was difficult then. French western Atlantic ports acted an bases for Dutch shipping yet one was Catholic and the other was Protestant. After the success of the Portugese rebellion in 1640, Dutch traders traded directly with the Iberian peninsula via Portugal.
However, the impact on Dutch and Spanish trade was such that by the 1640's both parties sought a settlement to allow them to expand their merchant fleets again in times of peace. In particular, the Dutch were acutely aware that the value of shares in the Dutch West Indian Company had decreased markedly and the powerful merchant families in Amsterdam flexed their political clout. Peace could only bring a return to prosperity.