The peak of Spanish power is usually dated with the reign of King Philip II, yet in terms of the size of the Spanish Empire, that peak was reached during the reign of his successor King Philip IV. He reigned at a crucial time. After the death of the dominant Philip II, Spain is generally considered to have gone into decline due to the often unscrupulous ministers (especially the Duke of Lerma) who dominated the country during the reign of Philip III. When it came time for his son to take the throne he was pulled in opposite directions and went back and forth between the noninvolvement of his father and the quality of his grandfather.
Philip IV was born on April 8, 1605 in Valladolid to King Philip III and Margaret of Austria. When he was only ten years old he married Isabella of France in 1615. The couple had seven children, 6 girls and 1 boy who sadly died in 1646 when he was only 16-years-old. Despite being pushed toward temptation in many ways, King Philip IV corresponded with Venerable Mary of Agreda; a Spanish mystic who advised him on how to be good Catholic monarch. Yet, he was not always a hard enough man to bear the burdens of his office and found diversion in riding, hunting, the theatre and being a great patron of the arts. He also, like his father, placed a great deal of power in the hands of his chief minister the Duke of Olivares. Thankfully, however, Olivares was a more noble man than Lerma had been. However, Queen Isabella and a clique of powerful nobles managed to have Olivares removed in 1643 and she became a much more dominant figure until her own death the following year.
Still wishing to maintain the Austrian alliance, in 1646 King Philip IV married Maria Anna of Austria, his niece and the daughter of the Hapsburg Holy Roman Emperor Ferdinand II. Yet, Philip still had trouble producing an heir with his only surviving son of six pregnancies, Prince Carlos Jose, being often in poor health. As monarch his government was plagued by the financial problems he inherited from the Lerma regime which left Spain strapped for cash and heavily dependent on gold and silver imports from Latin America to fund continental obligations. These Spain certainly had for, while Philip IV could often be an absent monarch like his father, he also tried to carry on a foreign policy more like Philip II, fighting for the restoration of Catholic Christendom in the Thirty Years War alongside Emperor Ferdinand II. The Spanish contribution largely consisted in renewing the war against the Dutch republic which had previously broken away from the Spanish empire.
Spain won a number of victories over the Dutch and even marched into Germany to support the Emperor against the intervention of the Swedes on the Protestant side. However, this ultimately led to war with King Louis XIII of France and Spanish troops and finances were stretched to the limit and uprisings broke out in areas already conquered and even in Spain itself. Peace was finally agreed to with the Dutch and a renewed effort was made against France but no decisive victory was forthcoming. Philip IV was finally forced to make peace, sealed by a marriage between his daughter and King Louis XIV of France. Spain itself and the war effort suffered greatly from financial problems, particularly as English and Dutch warships raided the Spanish treasure fleets Philip IV heavily depended on.
Despite a very eventful reign, what Philip IV will probably be most remembered for is his great love of art. He was patron to a number of artists, loved artwork and the theatre and during his life amassed an extensive and very impressive art collection of his own. He gained renown across Europe and the world for the majestic grandeur of his court, an image which he owed to a large extent to his many large and magnificent paintings. Unfortunately, these were expenses he could not afford and despite the success of his early years Spain was going into visible decline by the time of his death on September 17, 1665 at the age of 60 in Madrid. He was buried in El Escorial and succeeded by his son King Carlos II, the last Spanish Hapsburg.