One king and one faith was the organizing principle for the monarchies of western Europe. The Protestant Reformation destroyed the easy unanimity of political power and religious faith. As European populations were divided in religious belief, internal disruption of the state and society was inevitable. Only the total victory of Catholics or a single variety of Protestantism could restore the solidarity of the state and society. As rulers choose the religion of their state, religious minorities were forced to uproot and migrate. The resulting bitterness and chaos produced a century of civil wars.

Protestantism was exported to France from Calvin’s Geneva. By 1560 Calvinism had gained a foothold in France, particularly within the provincial towns. At the same time, the death of the reigning French monarch Henry II, left his fifteen-year-old son and his widowed queen, Catherine de Medicis, in control of the royal administration. The weakened central government permitted the creation of a powerful political faction within the French aristocracy. The Catholic Guise family allied itself with the royal family and dominated the offices of state and of the Catholic Church in France. The Guises were intent on the destruction of Protestant nobles who represented a possible opposition. Their situation became less secure when Francis II died, leaving his younger brother, Charles IX, on the throne. Sensing the weakness of the Guise position, Protestant nobles led by the Bourbon family and Henry of Navarre raised armies and initiated a civil war in 1562. Neither side was able to gain a decisive advantage. The Protestants were reduced to defending cities in their control, largely in southern France. Catherine de Medicis unsuccessfully sought a truce that would guarantee the position of her remaining sons. An attempted compromise that would permit Protestantism among the nobility was undone when the head of the Guise family was assassinated. A second diplomatic effort was initiated in 1570. Henry of Navarre was offered the hand of Charles IX’s sister with the wedding to take place in Paris. The proposed marriage proved to be a deception intended to lure Protestant leaders to the capital city where they could be slaughtered by the Guise retainers. The result was the Saint Bartholomew’s Day Massacre of 1572. Many Protestants were murdered in the streets, but the leaders escaped.

The collusion of Catherine de Medicis in the Saint Bartholomew’s Day Massacre allowed Henry of Navarre and the Huguenots (as French Protestants were called) to launch an attack on the monarchy itself. Some moderate Catholic nobles, appalled by the bloodshed in Paris, joined forces with the Huguenots. Conservative Catholics responded by forming the Catholic League. The League, still led by the Guise family, was even willing to alter the succession in order to avoid any compromise with the Protestants. The monarchy seemed on the verge of losing its authority to one or another of the parties. King Henry III ordered the assassination of the leading members of the Guise family and attempted to gain a treaty with Henry Bourbon and the Huguenots. The sad chronicle of political duplicity and murder reached its climax with the assassination of the king in 1589. The sole successor to the Valois throne was Henry Bourbon, king of Navarre and leader of the Huguenots. In order to make his claim acceptable, Henry IV renounced Protestantism and converted to Catholicism. Such a diplomatic conversion, however much it may have lacked in sincerity, allowed Henry to claim the support of the papacy and the moderate Catholics. Resistance to the monarchy collapsed. In 1589, Henry made the settlement as palatable as possible to the Huguenots by offering them limited toleration in the Edict of Nantes. The passions of religious division were not entirely calmed. An assassin murdered Henry IV in 1610.

Spain under King Philip II was the most powerful nation in sixteenth-century Europe. His domain included Naples, Milan, the Netherlands, Portugal, and the colonies of the New World. Philip exercised a personal supervision over the affairs of his far-flung empire. Philip also presented himself as the protector of Catholicism and the scourge of Protestantism. Briefly married to Mary I, the Catholic queen of England, Philip hoped to retain England for Catholicism and as a Spanish ally. When Mary’s successor, Elizabeth I, returned England to the Protestant Anglican Church and allowed English pirates to attack Spanish shipping, Philip amassed a great armada to attempt an amphibious assault on England. The Armada was largely destroyed by weather and English ships in 1588.

Philip’s attempts to secure Catholic orthodoxy were particularly problematic in the Low Countries. The source of conflict was the rapid dissemination of Calvinism in the tolerant communities of the Low Countries and Philip’s attempts to enforce the decrees of the Council of Trent. Both the local nobility and the town governments refused to implement the repressive measures of Philip’s decrees.

A Calvinist assault on Catholic churches initiated violence. The Spanish government viewed the iconoclasm as open rebellion with the tacit approval of the local nobility. Philip dispatched an army under the command of the Duke of Alba to restore order and orthodoxy. Alba imposed a martial reign of terror. Protestant nobles and suspected revolutionaries were executed under the authority of the military tribunal, the Council of Blood. In the short term, brutal suppression of Protestantism was effective. The Protestant movement was supported by those who resented not only the presence of the Spanish army, but also the taxation required to support it. In 1572 a full-scale civil war between the Spanish regents and Protestants ensued. Prince William of Orange led the Protestant movement, centered in the provinces of Holland and Zeeland. Alba’s failure led to his removal from command, but undisciplined Spanish troops continued to loot the towns of the southern Low Countries. Brussels, Ghent, and Antwerp were sacked. The unrestrained violence of the Spanish army so discredited the Spanish presence in the Netherlands that Philip II granted autonomy in the Pacification of Ghent of 1576. What remained was a divided territory. Five provinces agreed to remain Catholic and recognize the authority of the Spanish monarch. The remainder declared their independence. Despite continual military efforts to bring the northern provinces back under the aegis of the Spanish government, Holland remained independent. The war was economically ruinous for all involved.

Dynastic struggles more than religious discord troubled the states of eastern Europe.

In 1572 Sigismund II, the last of the Jagiellons, died. In the absence of an heir, the Polish nobility elected the royal successors from available nobility elsewhere in Europe. In return for aristocratic favor, successful candidates conceded constitutional and religious rights to the nobility. The Polish Diet, a representative body of nobles, gained many powers, including the right to establish a policy of religious toleration. Throughout the sixteenth century, Poland-Lithuania remained militarily and economically strong. In 1587 Sigismund III, also heir to the Swedish crown, was elected king in Poland-Lithuania. While he accepted the principle of religious toleration, he acted to strengthen Roman Catholicism. Poland resolutely refused to support Sigismund’s attempts to enforce his claims in Sweden.

Following the death of Ivan IV, the Terrible, the principality of Muscovy began to disintegrate. With no capable heir and without the support of the Muscovite aristocracy, the central government disintegrated. After 1601 numerous claimants to the throne battled with one another for superiority in the period referred to as the Time of Troubles. Poland-Lithuania sought to capitalize on the problems within Muscovy and to retake lands lost in the past. The Polish monarch, Sigismund III, turned from abortive campaigns in Sweden to an assault on Muscovy. When a plan to support one of the Muscovite claimants to the throne failed, Sigismund took Moscow and had himself proclaimed tsar in 1610. Sigismund III’s reign as tsar of Muscovy was short-lived. In 1613 the Russian boyars united against a foreign enemy and elevated Michael Romanov to the office of tsar. Romanov was able to arrange for a peace with Poland in exchange for territorial concessions.

Sweden had been part of a Danish confederation until the rebellion of Gustav I Vasa in 1523. Thereafter Gustav ruled an independent Sweden in tandem with the Swedish aristocracy, who voiced their concerns through the Rad. Under Gustav, Sweden launched an aggressive foreign policy aimed at dominating the Baltic Sea regions. With the failure of the Teutonic Knights in Livonia, Sweden gained a foothold in Livonia on the Gulf of Finland through the fortification of sea ports on the Livonian coast. Sweden was soon drawn into conflict with Poland and Denmark over control of Baltic trade. Sigismund III of Poland had a claim to the Swedish throne. The Swedish aristocracy rebuffed Sigismund’s attempts to secure both crowns and elected Charles IX in 1604. The election provoked conflict with Poland, but gave the Swedes an opportunity to extend their control over Livonia. Their primary objective was the port of Riga, a major center of eastern trade. Although the Swedish navy enjoyed success, the Poles destroyed their land forces. Only the Polish invasion of Muscovy saved the Swedes from loss of Livonia. Just as the Swedes were involved in the conflict with Poland, the king of Denmark, Christian IV, attempted to renew Danish claims to sovereignty in Sweden. In order to avoid a war on two fronts, the Swedes gave away nearly all of their trade advantages in the Baltic to Denmark in 1613. King Gustavus Adolphus (1611- 1632) succeeded Charles IX in the midst of the northern conflicts. With the invaluable support of the English and the Dutch—both of whom had trade interests in the Baltic—Gustavus Adolphus led the Swedes to military victory in the north. Renewed war with Poland ended the claims of Sigismund III to the Swedish throne and garnered the port of Riga. Muscovy surrendered its territories in the Gulf of Finland in return for Swedish support against the Poles. By 1619, Sweden was firmly in control of the eastern Baltic.

European warfare between 1555 and 1648 combined the worst aspects of dynastic and religious conflict. Long years of dynastic struggle for hegemony and internal religious strife came to a head in the Thirty Years’ War.

The Holy Roman Empire remained fragmented religiously and politically. The Peace of Augsburg guaranteed to each prince the right to determine the religious orthodoxy of his principality. The empire remained, as it had since the Golden Bull of 1356, decentralized. At the beginning of the seventeenth century, the head of the empire, the Habsburg emperor, presided over the eastern states of Austria, Bohemia, and Hungary. To secure the succession for his Catholic nephew, Emperor Mathias granted the monarchy of Bohemia to Ferdinand Habsburg. A staunch Catholic, Ferdinand rapidly alienated the Protestant majority of his new kingdom. A group of Protestant nobles rebelled against Ferdinand’s government and physically threw two officials out of a window in the royal palace. This assault, the Defenestration of Prague, signaled the start of Protestant revolts throughout the Habsburg domains. Spain immediately joined their imperial Habsburg relatives to put down the Bohemian rebellion. In 1619 Ferdinand succeeded Mathias as Holy Roman Emperor. At the same moment, Frederick of the Palatinate, a Protestant prince, accepted the vacant Bohemian throne. War between Ferdinand and Frederick was inevitable. The first stage of the conflict that became known as the Thirty Years’ War was a complete victory for the Catholic allies over the Bohemian pretender. Ferdinand’s forces conquered their adversaries at the Battle of White Mountain and sacked Bohemia, which was added once again to the Habsburg estates. The victory of the Catholic emperor caused Protestant princes to seek potential allies in case the ruler wished to press his advantage in the empire.

To meet the Spanish and imperial Habsburg challenge, a group of Protestant allies—England, Holland, Denmark, and some German principalities—determined to carry on the conflict. In 1626 a Danish army invaded the empire. Under the command of Albrecht von Wallenstein, the imperial forces easily dispatched the Danish threat. By 1629, the Danes withdrew as leaders of the Protestant coalition. The emperor used his military superiority to reduce the influence of Protestantism within the borders of the Holy Roman Empire. Toleration for Calvinists was revoked, and all lands taken from the Catholic Church had to be returned. German Protestants had little choice but to unite in opposition to the emperor. In 1630 Gustavus Adolphus of Sweden assumed the leadership of the scattered Protestant alliance. Sweden’s monarch hoped both to defend the northern tier of German Protestant principalities and simultaneously to protect Swedish interests in the Baltic. A wartime atrocity at the Protestant city of Magdeburg galvanized the Protestant opposition. Saxony and Brandenburg, previously hesitant to join the conflict, entered on the side of the Swedes. By 1631 the Protestant forces were able to seize the initiative and invade Catholic territories. The Palatinate was recaptured and Catholic Bavaria fell to the Protestant invaders. In the midst of his success, Gustavus Adolphus was killed at the battle of Lutzen.

The theater of war changed from central Europe to the west. In 1621 the Spanish renewed their war with the provinces of Holland. Distracted by the early stages of the Thirty Years’ War, the Spanish were unable to bring all of their military forces to bear on Holland. The naval superiority of the Dutch led to a series of Spanish setbacks. The Dutch razed Spanish colonies and attacked the New World treasure fleets. In 1627 the expenses of warfare so strained the Spanish treasury that Philip III declared bankruptcy. France declared war on Spain in 1635. The primary location of war between France and Spain was the Spanish Netherlands. Neither side was able to gain a military advantage, but the effects of many years of war were harsher for the Spanish. The Dutch won another victory at sea over the Spanish fleet in 1639. At the same time, the Portuguese rebelled in order to regain their independence. By 1640 all of the rulers and major figures at the outset of the Thirty Years’ War had died. Those who succeeded them wanted nothing more than to end the war. Unfortunately, each monarch wanted to gain an advantage out of the peace. Only in 1648 was the Peace of Westphalia hammered out. It generally recognized Protestant and French gains at the expense of the Habsburgs. Spain agreed irrevocably to Dutch statehood. Sweden gained its superiority over the Baltic ports of northern Germany. France gained territories in the Lower Palatinate that closed the Spanish military highway to the Low Countries. Within the empire, the terms of the Peace of Augsburg were restored and explicitly extended to include Calvinists. The powers of the emperor were further weakened in favor of the princes.