During the Middle Ages, Spain had little influence on European history. The reason for this is that the country is isolated from European countries because of its location on the border of Europe and the fact that the Perinis Mountains stretch across the northern border. Moreover, since the beginning of the 8th century, Spain has been ruled by the Moors, the Islamists of North Africa. In the 8th century, because the Arabs conquered North Africa, they converted to Islam and crossed the sea with the Arabs to conquer Spain), and for a long time they were hostile to the Christian European countries, which affected the exchanges between Spain and European countries.
In fact, the term "Spain" was no more than a geographical term until the 15th century ("Spain" (Hispania was still the local Phoenician name, later adopted by the Romans, and "Iberia" by the Greeks, and "Al-Andalus" by the Arabs and Moors). On the peninsula, there are many countries, and in addition to the regime established by the Moors, a number of Christian states remain in the northwest, waiting for an opportunity to counterattack.
By the beginning of the 15th century, the Moors had declined and shrunk to Granada at the southern tip. In 1469, Ferdinand (succeeding Ferdinand II) and Isabella (successor is Known as "Isabella I") in Castile (present-day Central Spain) (note: the so-called "Spanish" or Castile) were united.
The latter two joined the unification in 1479 and 1474 respectively, and combined the strength of the two countries to become the most powerful state in Spain (Note: Generally 1479 is the beginning of the founding of modern Spain). In order to unite the centripetal force of the people, and vow to expel the Moorish/Islamic forces out of Spain, Castile. Aragon conquered Granada between 1481 and 1492. Later Ferdinand took possession of Navarre in northwestern Navarre (territory including present-day Basque Country) in 1512. Thus established the borders of present-day Spain.
By the time Ferdinand and Isabella's grandson Charles V (Spanish known as Carlos I) and his son Philip II (reigned 1556-1598) were in operation, Spain gradually formed a unified "nation-state".
After the conquest of Granada in 1492, Spain rose to prominence in Europe between the 15th and 17th centuries, and began to decline by the middle of the 17th century (in fact, it had begun to decline since the end of the 16th century). Spain's decline is an interesting lesson in European history, and even into the 21st century, its experience is still worthy of borrowing from today's people.
Geography was one of the reasons why Spain exploded in the 15th century. As mentioned earlier, the country is located on the edge of Europe, bordering the Atlantic Ocean. In the past, due to the limitations of geographical knowledge, Spain was regarded as the end of the earth and the end of the world. However, with the decline of the Byzantine Empire, the Eastern Roman Empire, which ruled Greece, a large number of Greek scholars fled to Western Europe (Note: The Byzantine Empire was destroyed by the Ottoman Empire in 1453); together with the preservation and translation of Islamic scholars, the writings of ancient Greece and Rome, including the writings of Claudius Ptolemy in geography, were re-circulated in Europe. It helps Europeans to improve their knowledge of foreign geography.
In addition, inspired by Marco Polo's dictated Travels of Marco Polo (also known as "The Travels of Marco Polo"), it inspired Europeans to take risks and explore in search of the legendary "El Dorado". As a result, Spain (and Portugal), which is bordering the Atlantic Ocean, is no longer seen as the end of the world, but a stepping stone for outward exploration!
With this advantage, the Italian navigator Christopher Columbus, with the support of the Spanish royal family, crossed the Atlantic Ocean in 1492 and accidentally "discovered" the American continent. Columbus's "discovery" not only allowed Spain to open a new route, but also monopolized the opportunity of the colony. Within a century, Spain also established a vast colonial empire from present-day California to Central America and argentina. Among them, the Spaniards conquered Mexico and Peru in 1519 and 1533 respectively, and found large deposits of gold in the area. By plundering large amounts of gold in the American colonies, Spain relied on this to become the most powerful country in Europe at that time!

The Spanish Empire of Philip II (1556-1598): Even Portugal and its colonial empire were once taken over by Spain (1581-1640), but in the eyes of their contemporaries, the English and Dutch were illusory
Charles V (known as Charles I in Spain): One of the most powerful monarchs in Europe at the beginning of the 16th century, as both Holy Roman Emperor and King of Spain, he was a diligent man, and although he was determined to govern in Spain, he laid the groundwork for the decline of Spain because of repeated foreign moves
Philip II: King of Spain, son of Charles V, because of his birth and upbringing in Spain, he had a paranoid Spanish patriotism and a fanatical attachment to the Catholic faith, and during his reign, although Spain's national strength reached its peak, it was already a strong foreign power
Since the time of Ferdinand and Isabella, successive Spanish royal families have pursued a strong centralized system. By establishing a national police system—recruiting citizens to form the Santa Hermandad, and stripping the Cortes and the Inquisition, which were made up of feudal nobles, the Spanish crown succeeded in suppressing the illegal excesses of the feudal nobility and establishing a strong central government.
During the 15th and 16th centuries, Spain was one of the few highly centralized European countries, and when other countries were still suffering from the chaos brought about by feudalism, Spain, which had a relatively stable social order, naturally expanded abroad!
In addition, as Spain had been engaged in wars against the Moors in the past, it had accumulated a great deal of experience and developed new "tercio or Spanish Square" tactics. Since the conquest of Granada, Spain has established a specialized national army consisting mainly of new infantry—musketeers and pikemen—in rectangular formations, centered in a central position; field artillery at the forefront; cavalry in the rear or flanks, used as snipers (rather than chargers). In battle, use parallel battles to orderly.
Since many European countries at that time, especially the Italian city-states, were rabble-rousers of mercenaries (Note: In the 15th-16th centuries, mercenaries were mostly recruited by leaders on an ad hoc basis to serve the high-priced, and once captured or fully engaged, they could be exchanged for food from the enemy. A typical example of this is Albrecht von Wallenstein, who recruited a large army in the Thirty Years' War (1618-1648) to serve the Holy Roman Emperor Ferdinand II and suppress protestants in Germania (Germany) and could not match the Spanish army!
Symbol of Spanish military power: "Spanish phalanx"
However, why did Spain decline in the 17th century? Many scholars analyze one of the main reasons for the decline, because wealth comes too easily, but it is not easy to use, but it is known to be used for unnecessary wars and wasted!
Since the time of Charles V, Spain has been at war with French, Turkish, English, Dutch, Swedish and Germanic Protestants for political and religious reasons, including the War of the League of Cognacy (1526-1530), the Eighty Years' War/Dutch War of Independence (1568-1648), the Anglo-Spanish War (1585-1604), the Thirty Years' War and the Franco-Spanish War (1635-1659)! In the wars, especially the Thirty Years' War and the Franco-Spanish War, which had a great influence on Spain: Spain fought against Protestantism in Europe and supported Austria (Note: During 1516-1700, the Spanish and Austrian royal families belonged to the House of Hapsburg, which was divided into Two branches in 1556, Austrian and Spanish, but maintained close ties, including intermarriage. The Austrian line has held the throne of the Holy Roman Empire for generations since 1438) and participated in the Thirty Years' War. Until the end of the war, Spain continued to fight alone with the pro-Protestant France until 1659, which finally severely damaged Spain's vitality and never had the advantage again!
In addition, the wealth of the Spaniards, all due to the plundering from the colonies, made them adventurous and disliked industrial and commercial development. In other words, its sudden wealth has not helped the country's economic development at all. On the contrary, because of the wealth and wealth, the extravagant money was imported from abroad for luxury goods, resulting in a large amount of wealth flowing out to England and the Netherlands and other countries. Coupled with the annual conquest, the domestic taxation is numerous, hindering the development of local industry and commerce!
However, precisely because Spain's financial resources depended on gold from the American colonies and neglected the development of industry and commerce, once the local gold sources dried up, the income could not be sustained.
Because it took the Spaniards 8 centuries to completely expel the Islamic forces from the country, they gradually formed the Spanish people's narrow religious and ethnic views. The Spanish royal family, and even the people, regard the country as an instrument of God, vowing to defend the Catholic faith and hostility to Protestantism!
This situation is most notable in the era of Charles V and Philip II (1516-1598): father and son, like the Spaniards, maintained strict Catholic faith, but Charles V, as Holy Roman Emperor (during his reign of 1520-1556), could not fully carry out this task; but Philip II was only king of Spain, and grew up in the land, and his thinking was more radical and narrow-minded than that of his father (Note: Charles V was born in present-day Belgium). In addition to participating in the war against Protestantism for religious reasons, he also persecuted and exiled jewish and Moorish subjects who were good at business at home, invisibly stifling economic development. In addition, Philip II's intolerant policies provoked protestant Dutch rebellions against Spain in 1568 (note: the Netherlands became Spanish territory in 1516), leading to the 80-year-long Dutch War of Independence, which exacerbated Spain's depleted financial resources
The autocratic monarchy established Spain as a unified state. But the country was, after all, a "union" country, but the Castilians enjoyed great advantages and were long dissatisfied with the Catalans and Portuguese (note: Spain had merged with Portugal between 1581 and 1640), which led to a revolt between the Catalans and the Portuguese, who are still incompatible. In addition, the high concentration of power also hindered the administration: in the case of Philip II, because Philip had to do everything himself, so that "everything was too big or small, every day was a chance", but his diligence hindered the development of Spain as a whole, making the administration slow and delaying the opportunity.
Finally, the decline of Spain's military power was also one of the reasons for its decline. Spanish navigation technology has been outdated since the 16th century, as evidenced by the defeat of the Armada. In 1588, Philip II formed an Armada expedition to stop england's rebellion in support of the Netherlands and the Catholics in England—a scale rare in history.
However, the Spanish ships were bulky — like a fortress , and tactically still relied on traditional boarding for hand-to-hand combat ( on the contrary , England 's ships were light , and the ship 's guns could be fired at long distances ) , resulting in heavy losses! Spain sometimes relied on foreign merchant ships to carry gold from the American colonies back home, and the occasional interception of plunder by English and Dutch pirates hit the tax. On the other hand, Spain's "phalanx" tactics, although once dominant— and even imitated by various countries, were slow to move and encountered enemies with high mobility, and they were at a disadvantage.
During the Thirty Years' War, the Spanish Army enjoyed an advantage in the early stages, but in the later stages, once faced with the more mobile Swedish Army, its bulky tactics were gradually at a disadvantage. Finally, in 1643, the Battle of Rocroi was defeated by the French army, the Swedish ally! The war also marked the decline of Spanish military power, which was replaced by French military power (until 1870).
Spanish military power symbol: the Armada
Spain was the leading country in Europe during the 15th and 17th centuries. However, the country declined due to its narrow religious, ethnic views and outdated economic policies. Unable to secure its empire, by the end of the 17th century, its colonial empire had become the object of contention between Britain, France, and the Netherlands.
In economics, the "Spanish experience" is still used as a reference for today's countries, because the national wealth came too easily, and the result was not good to use - some of them even threw money on luxury goods, and finally repeated the mistakes of Spain!
The most notable example is the small Pacific country of Nauru! The country's economy has always relied on the export of phosphate rock abroad – and its citizens don't even have to work, but since the 1990s, the mineral deposits have dried up, leaving the country with no way to go in the future (in return for Nauru's establishment of detention facilities in return for Australia's illegal refugees entering the country) in exchange for Australia's economic assistance?
The Middle Eastern country of the United Arab Emirates to rely on the export of "black gold" (oil) - to get rich (when I studied in the United States, according to classmates from the United Arab Emirates, the government even bears the tuition fees of students studying abroad), but recently actively developed finance and tourism, it seems that "Ugin" can not last long, there must be a need to prevent the decline of the oil industry.
Original works, please do not reprint
EDIT: History of the Great River